Animal model of longevity and related methods for increasing longevity and inhibiting tumorigenesis

ABSTRACT

A genetically-modified non-human animal model of longevity and increased health span, which is associated with reduced tumorigenesis and tumor metastasis, as well as related methods for increasing longevity and health span, reducing tumorigenesis and tumor metastasis, and identifying active agents that confer increased longevity or health span, or reduced tumorigenesis or tumor metastasis.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional Application of co-pending applicationSer. No. 15/507,650, filed on Feb. 28, 2017, for which priority isclaimed under 35 U.S.C. § 120, which claims priority to U.S. ProvisionalApplication No. 62/044,411, filed on Sep. 1, 2014, under 35 U.S.C. §119(e), which is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates to methods for enhancing life span,increasing health span, and inhibiting tumorigenesis and tumormetastasis, as well as novel non-human animal models of longevity andtumorigenesis, and methods of identifying therapeutic agents for use inenhancing life span or health span, or for use in inhibitingtumorigenesis or tumor metastasis.

BACKGROUND OF THE INVENTION

Longevity genes are of obvious interest and importance, both for theirlife-extension potential and the possibility of their contributing tothe enhancement of the quality of life. However, very few of these geneshave been identified and even less is understood about how these genesact to prevent aging and promote life extension. In addition, there is arelated need in the art for identifying genes associated with decreasedrisk of cellular proliferative disorders, including those associatedwith aging.

Accordingly, there exists the need to discover genes whose function isassociated with life-extension and/or reduction of cellularproliferative disorders. These genes and their products would be usefulin the screening for anti-aging and/or anti-cancer agents and wouldserve as key targets in various anti-aging and anti-cancer therapies. Inaddition, knowledge of these genes allows the development of animalmodels of disease, which can be used to further identify and studydisease pathways, and identify and validate therapeutic agents.Ultimately, such tools and therapeutic agents could help to alleviatecognitive and motor function deficits in the aged population, and reducethe incidence or metastasis of cancer in both the aged and the generalpopulation, thereby prolong the independence of the elderly andenhancing health.

BRIEF SUMMARY OF THE INVENTION

A first aspect of the present invention provides a non-human transgenicanimal comprising one or more modified Erythroid Kruppel-like factor(EKLF) gene alleles encoding a modified EKLF polypeptide comprising oneor more amino acid modifications as compared to a wild-type EKLFpolypeptide. In certain embodiments, the wild-type EKLF polypeptide isfrom the same genus or species of animal as the non-human transgenicanimal. In particular embodiments, the non-human transgenic animal is aknock-in animal. In certain embodiments, one or more endogenous EKLFgene alleles of the animal are replaced by the one or more modified EKLFgenes. In particular embodiments, the expression of the one or moremodified EKLF gene alleles is under the control of an endogenous EKLFpromoter. In certain embodiments, both endogenous EKLF gene alleles arereplaced by the modified EKLF genes. In one embodiment, the non-humantransgenic animal is a knock-in animal wherein both alleles of the EKLFgene are modified as compared to the wild-type, such that they encode amodified EKLF polypeptide described herein, e.g., a modified EKLFpolypeptide comprising a mutated sumoylation site that is notsumoylated. In certain embodiments, the animal is a rodent, optionally amouse or a rat.

In particular embodiments of the first aspect of the present invention,the one or more amino acid modifications comprise a modification at anamino acid position that is sumoylated or phosphorylated in thewild-type EKLF polypeptide. In one embodiment, the one or more aminoacid modification comprises a modification of an amino acidcorresponding to position 74 of the full length wild-type mouse EKLFpolypeptide. In certain embodiments related to animals other than mice,the one or more amino acid modification comprises a modification of asumoylated amino acid residue corresponding to this residue in the mouseEKLF polypeptide, but it may be located at a different position. Forexample, in the human EKLF polypeptide, the sumoylation sitecorresponding to position 74 in the mouse EKLF polypeptide is located atamino acid residue 54. In particular embodiments, it is a Lys residue.In certain embodiments, the modification of the amino acid correspondingto position 74 is a substitution of Lys with Arg (K74R). In particularembodiments, the one or more amino acid modification comprises amodification of an amino acid corresponding to position 68 of the fulllength wild-type mouse EKLF polypeptide. In one embodiment, the presentinvention includes a homozygous knock-in mouse comprising the amino acidsubstitution K74R in both EKLF gene alleles. In certain embodimentsrelated to animals other than mice, the one or more amino acidmodification comprises a modification of a phosphorylated amino acidresidue, e.g., an amino acid residue corresponding to this residue inthe mouse EKLF polypeptide, but it may be located at a differentposition.

In certain embodiments of first, second, third or fourth aspects of thepresent invention, the modified EKLF polypeptide has reduced sumoylationor reduced phosphorylation as compared to the wild-type EKLFpolypeptide. In certain embodiments, the modified EKLF polypeptide hasreduced translocation from the cytoplasm to the nucleus as compared tothe wild-type EKLF polypeptide, and/or a modified transactivatoractivity or a modified repressor activity as compared to the wild-typeEKLF polypeptide. In related embodiments, the presence or expression ofthe modified EKLF polypeptide is associated with an increased lifespanor increased health span of the non-human transgenic animal, or theexpression of the modified EKLF polypeptide is associated with reducedtumor occurrence, tumor growth or reduced tumor metastasis in thenon-human transgenic animal, as compared to wild-type animals.

In a second aspect, the present invention includes a knock-in vectorcomprising a polynucleotide sequence encoding a modified EKLFpolypeptide, or a portion thereof, comprising one or more amino acidmodifications as compared to a wild-type EKLF polypeptide.

In a related third aspect, the present invention includes a cell, tissueor organ derived from a non-human transgenic animal described herein.

In a fourth aspect, the present invention provides a method of treatingor preventing a cellular proliferative disorder, or inhibiting orreducing the incidence of tumor occurrence or metastasis, in a subjectin need thereof, comprising administering to the subject an effectiveamount of: a polypeptide or a nucleic acid encoding the polypeptide,wherein the polypeptide is a modified EKLF polypeptide comprising one ormore amino acid modifications that confer decreased sumoylation of themodified EKLF polypeptide as compared to a wild-type EKLF polypeptide;and/or a first active agent that alters one or more activities of anendogenous or wild-type EKLF polypeptide. In certain embodiments, themodified EKLF polypeptide is a modified human EKLF polypeptide, and incertain embodiments, the first active agent alters one or moreactivities of a wild-type human EKLF polypeptide. In some embodiments,the cellular proliferative disorder is a tumor or a tumor metastasis,such as but not limited to, a liver cancer, a colon cancer, a breastcancer, a prostate cancer, a hepatocellular carcinoma, a melanoma, alung cancer, a glioblastoma, a brain tumor, a hematopoetic malignancy, acholangiocarcinoma, a retinoblastoma, a renal cell carcinoma, a head andneck cancer, a cervical cancer, a pancreatic cancer, an esophagealcancer, or a squamous cell carcinoma.

In particular embodiments of the fourth aspect wherein the polypeptideor the nucleic acid is administered, the modified EKLF polypeptide hasreduced translocation from the cytoplasm to the nucleus as compared tothe wild-type EKLF polypeptide. In certain embodiments, the modifiedEKLF polypeptide has a modified transactivator activity or a modifiedrepressor activity as compared to the wild-type EKLF polypeptide. In oneembodiment, the nucleic acid is an expression vector. In one embodiment,the expression vector is a viral vector. In particular embodiments, theviral vector is derived from a herpes virus, a retrovirus, a vacciniavirus, an attenuated vaccinia virus, a canary pox virus, an adenovirus,or an adeno-associated virus.

In particular embodiments of the fourth aspect of the present invention,the one or more amino acid modifications comprises a modification at anamino acid position that is sumoylated or phosphorylated in thewild-type EKLF polypeptide, e.g., the wild-type human EKLF polypeptide.In certain embodiments, the one or more amino acid modificationscomprises a modification of an amino acid corresponding to position 54of the full length wild-type human EKLF polypeptide. In one embodiment,the modification of the amino acid at position 54 is a substitution ofLys, e.g., with Arg (K54R). In certain embodiments, the one or moreamino acid modifications comprises a modification of an amino acid thatis phosphorylated, e.g., in the human EKLF polypeptide, such as, but notlimited to, a phosphorylated amino acid corresponding to position 68 ofthe full length wild-type mouse EKLF polypeptide.

In particular embodiments of the fourth aspect where the first activeagent is administered, the first active agent reduces translocation ofthe endogenous EKLF polypeptide from the cytoplasm to the nucleus. Incertain embodiments, the first active agent modifies a transactivatoractivity or modifies a repressor activity of the endogenous EKLFpolypeptide. In some embodiments, the first active agent binds to theendogenous EKLF polypeptide. In various embodiments, the first activeagent is a small organic molecule or a polypeptide, optionally anantibody or a functional fragment thereof In certain embodiments,binding of the first active agent to the endogenous EKLF polypeptideinhibits its translocation from the cytoplasm to the nucleus.

In certain embodiments of the fourth aspect wherein the polypeptide orthe nucleic acid is administered, or wherein the first active agent isadministered, the method further comprises administering a second activeagent that inhibits expression of the endogenous EKLF polypeptide. Inparticular embodiments, the second active agent is a nucleic acidmolecule, optionally an antisense RNA, siRNA, shRNA or miRNA that bindsan mRNA encodes the endogenous EKLF polypeptide or a complement thereofthat. In one embodiment, the EKLF cDNA or mRNA sequence is the humansequence provided in GenBank Acession No. BC033580.1.

Certain embodiments of the fourth aspect of the present inventionfurther comprise administering to the subject an effective amount of ananti-proliferation agent suitable for treating the cellularproliferative disorder. In particular embodiments, theanti-proliferation agent is an alkylating agent, a topoisomeraseinhibitor, an anti-metabolite, or a cytotoxicity antibiotic. In certainembodiments, the alkylating agent is cisplatin, carboplatin,oxaliplatin, mechlorethamine, cyclophosphamide, melphalan, chlorambucil,ifosfamide, busulfan, N-nitroso-N- methylurea (MNU), carmustine,lomustine, semustine, fotemustine, streptozotocin, dacarbazine,mitozolomide, temozolomide, thiotepa, mytomycin, or diaziquone. Inparticular embodiments, the topoisomerase inhibitor is camptothecin,irinotecan, topotecan, etoposide, doxorubicin, teniposide, novobiocin,merbarone, or aclarubicin. In certain embodiments, the anti-metaboliteis fluoropymidine, deoxynucleoside analogue, thiopurine, methotrexate,or pemetrexed. In particular embodiments, the cytotoxicity antibiotic isactinomycin, bleomycin, plicamycin, mitomycin, doxorubicin,daunorubicin, epirubicin, idarubicin, piraubicin, alcarubicin, ormitoxantrone.

In a fifth aspect, the present invention includes a method of extendingthe lifespan or health span of a subject, comprising administering tothe subject an effective amount of: a polypeptide or a nucleic acidencoding the polypeptide, wherein the polypeptide is a modified EKLFpolypeptide comprising one or more amino acid modifications that conferreduced sumoylation of the modified EKLF polypeptide as compared to awild-type EKLF polypeptide; and/or a first active agent that alters oneor more activities of an endogenous EKLF polypeptide. In certainembodiments, the modified EKLF polypeptide is a modified human EKLFpolypeptide, and in certain embodiments, the first active agent altersone or more activities of a wild-type human EKLF polypeptide.

In particular embodiments of the fifth aspect wherein the polypeptide orthe nucleic acid is administered, the modified EKLF polypeptide hasreduced translocation from the cytoplasm to the nucleus as compared tothe wild-type EKLF polypeptide. In certain embodiments, the modifiedEKLF polypeptide has a modified transactivator activity or a modifiedrepressor activity as compared to the wild-type EKLF polypeptide. In oneembodiment, the nucleic acid is an expression vector. In one embodiment,the expression vector is a viral vector. In particular embodiments, theviral vector is derived from a herpes virus, a retrovirus, a vacciniavirus, an attenuated vaccinia virus, a canary pox virus, an adenovirus,or an adeno-associated virus.

In particular embodiments of the fifth aspect of the present invention,the one or more amino acid modifications comprises a modification at anamino acid position that is sumoylated or phosphorylated in thewild-type EKLF polypeptide, e.g., the wild-type human EKLF polypeptide.In certain embodiments, the one or more amino acid modificationscomprises a modification of an amino acid corresponding to position 54of the full length wild-type human EKLF polypeptide. In one embodiment,the modification of the amino acid at position 54 is a substitution ofLys, e.g., with Arg (K54R). In certain embodiments, the one or moreamino acid modifications comprises a modification of an amino acid thatis phosphorylated, e.g., in the human EKLF polypeptide, such as, but notlimited to, a phosphorylated amino acid corresponding to position 68 ofthe full length wild-type mouse EKLF polypeptide.

In particular embodiments of the fifth aspect where the first activeagent is administered, the first active agent reduces or inhibitstranslocation of the endogenous EKLF polypeptide from the cytoplasm tothe nucleus. In certain embodiments, the first active agent modifies atransactivator activity or modifies a repressor activity of theendogenous EKLF polypeptide. In some embodiments, the first active agentbinds to the endogenous EKLF polypeptide. In various embodiments, thefirst active agent is a small organic molecule or a polypeptide,optionally an antibody or a functional fragment thereof. In certainembodiments, binding of the first active agent to the endogenous EKLFpolypeptide inhibits its translocation from the cytoplasm to thenucleus.

In certain embodiments of the fifth aspect wherein the polypeptide orthe nucleic acid is administered, or wherein the first active agent isadministered, the method further comprises administering a second activeagent that inhibits expression of the endogenous EKLF polypeptide. Inparticular embodiments, the second active agent is a nucleic acidmolecule, optionally an antisense RNA, siRNA, shRNA or miRNA that bindsan mRNA or complement thereof that encodes the endogenous EKLFpolypeptide.

In particular embodiments of the fifth aspect of the present invention,the method results in reduced graying of the hair, increased motorcoordination, increased muscle strength, reduced muscle weakness,increased motor coordination, reduced osteoporosis, greater bone volume,greater bone density, greater trabecular number, reduced trabecularspacing, or reduced loss of balance in the subject.

In certain embodiments of the fourth or fifth aspects, the subject is amammal, optionally a human.

In a further related sixth aspect, the present invention includes amethod of identifying an active agent capable of increasing longevity,enhancing life span or health span and/or inhibiting or reducingtumorigenesis or tumor occurrence or tumor metastasis of a subject,comprising: contacting an EKLF polypeptide or a cell expressing an EKLFpolypeptide with a candidate agent; and measuring an amount ofpost-translational modification present on the EKLF polypeptide, ormeasuring an amount of an activity of the EKLF polypeptide, wherein ifthe amount of the post-translational modification or the amount of theactivity is altered as compared to a control amount, the candidate agentis an active agent capable of increasing longevity or life span and/orinhibiting tumorigenesis or tumor metastasis of the subject. Inparticular embodiments, the EKLF polypeptide is a wild-type human EKLFpolypeptide, or a variant or fragment thereof. In particularembodiments, the amount of post-translational modification is measured,and the candidate agent is the active agent if the measured amount islower than the control amount. In some embodiments, the measuredpost-translational modification is sumoylation or phosphorylation. Inparticular embodiments, the sumoylation occurs at an amino acidcorresponding to position 54 of the human EKLF polypeptide. In certainembodiments, the measured activity is translocation of the EKLFpolypeptide from the cytoplasm to the nucleus, and the candidate agentis the active agent if the measured amount is lower than the controlamount. In particular embodiments, the measured activity istransactivator activity, and the candidate agent is the active agent ifthe measured amount is modified, optionally less than, the controlamount. In certain embodiments, the measured amount is repressoractivity, and the candidate agent is the active agent if the measuredamount is modified, optionally greater than, the control amount. Invarious embodiments, the control amount is a pre-determined value, or anamount associated with an EKLF polypeptide, e.g., a wild-type human EKLFpolypeptide or fragment thereof, or cell not contacted with thecandidate agent. In some embodiments, the EKLF polypeptide is anendogenous EKLF polypeptide or an exogenous EKLF polypeptide. In someembodiments, the exogenous EKLF polypeptide is a wild-type EKLFpolypeptide. In certain embodiments, the cell comprises an exogenousnucleic acid capable of expressing the EKLF polypeptide.

In a related seventh aspect, the present invention includes a method ofidentifying an active agent capable of increasing longevity, extendingthe lifespan, enhancing the health span and/or inhibiting tumorigenesisor tumor occurrence or tumor metastasis of a subject, comprising:administering a candidate agent to a non-human transgenic animaldescribed herein (e.g., a non-human animal of first aspect); andcomparing the lifespan of the non-human transgenic animal after theadministration of the candidate agent with that of a control animal,which was not administered the candidate agent, wherein if the lifespanof the non-human transgenic animal that was administered the candidateagent is longer than that of the control animal, then the candidateagent is the active agent capable of increasing longevity, extending thelifespan, enhancing the health span and/or inhibiting tumorigenesis ofthe subject.

In a further related eighth aspect, the present invention includes amethod of identifying an active agent capable of increasing longevityand/or inhibiting tumorigenesis or tumor metastasis of a subject,comprising: contacting a cell capable of expressing a modified EKLFallele encoding a modified EKLF polypeptide comprising one or more aminoacid modifications as compared to a wild-type EKLF polypeptide with acandidate agent; and measuring the expression level of the modified EKLFpolypeptide, wherein if the expression level of the modified EKLFpolypeptide is higher than the expression level in a control cell notcontacted with the candidate agent, the candidate agent is an activeagent capable of increase longevity and/or inhibiting tumorigenesis ofthe subject. In particular embodiments of the eighth aspect of thepresent invention, the one or more amino acid modifications comprises amodification at an amino acid position that is sumoylated orphosphorylated in the wild-type EKLF polypeptide, e.g., the wild-typehuman EKLF polypeptide. In certain embodiments, the one or more aminoacid modifications comprises a modification of an amino acidcorresponding to position 54 of the full length wild-type human EKLFpolypeptide. In one embodiment, the modification of the amino acid atposition 54 is a substitution of Lys, e.g., with Arg (K54R). In certainembodiments, the one or more amino acid modifications comprises amodification of an amino acid that is phosphorylated, e.g., in the humanEKLF polypeptide, such as, but not limited to, a phosphorylated aminoacid corresponding to position 68 of the full length wild-type mouseEKLF polypeptide.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1D show the generation of EKLF K74R mice by homologousrecombination. (FIG. 1A; top) Depicts the EKLF gene locus and thetargeting locus. (FIG. 1A; bottom) Depicts the recombinant allele priorto (I) and after (II) Cre-mediated recombination. The protein-encodingportion of exon 2 of the EKLF gene was replaced by loxP-PGK-gb2-neo-loxPEKLF K74R retroviral vector and a neomycin cassette (Neo, open box)flanked by lox P sites (black box). The hatched regions indicate theportion of the endogenous EKLF locus that was deleted, and the portionof the targeting vector that was inserted in to the EKLF locus, bothbefore (I) and after (II) treatment with Cre recombinase to excise theneomycin cassette by Cre-mediated recombination. Nfix refers to the Nfixgene locus. Fbwx9 refers to the Fbwx9 gene locus. E1, E2, and E3 refersto exon 1, exon 2, and exon 3 of the EKLF gene, respectively; Intron 1and Intron 2 refer to the first and second introns of the EKLF gene,respectively. Neo refers to neomycin cassette. PGK refers to theeukaryotic promoter PGK; gb2 refers to the gb2 prokaryotic promoter.Delete refers to the deletion of 50 nucleotides form intron 1 of EKLF;SFA, SRA, gt EKLF d 5′, gt EKLF 3′, gt EKLF PGK 5′, Kin 5′ and Kin 3′respectively refer to PCR primers for genotyping. Left and right arrowsrefer to location of genotyping primer, respectively. K74R indicates DNAmodification resulting K74R substitution. PolyA refers to PolyA region.LoxP refers to LoxP site. (FIG. 1B) Genotyping of the wild-type (+/+)mice, heterozygous EKLF K74R mice (Kin/+) and homozygous EKLF K74R mice(Kin/Kin). (FIG. 1C) E13.5 embryos of wild-type (WT) and homozygous EKLFK74R mice (Kin). (FIG. 1D) Relative levels of the EKLF mRNA of the WTand EKLF K74R mouse.

FIGS. 2A and 2B show that the EKLF K74R substitution affectstranscriptional activity of the EKLF polypeptide. (FIG. 2A) Relativelevels of mRNA of Col1a1 of E14.5 fetal livers of wild-type (WT) andEKLF K74R (Kin) mice. (FIG. 2B) Relative levels of mRNA of Mpv171 ofE14.5 fetal livers of wild-type (WT) and EKLF K74R (Kin) mice. Data werecollected from 3 independent experiments. **p<0.01, ***p<0.001.

FIGS. 3A and 3B show a comparison of lifespan between EKLF K74R (Kin)and wild-type littermates (WT). (FIG. 3A) Survival curves of the WT andKin mice are shown. (FIG. 3B) Images demonstrating delayedde-pigmentation in the Kin mice are shown.

FIGS. 4A-4D show analysis of wild-type (WT) and EKLF K74R (Kin)metabolism. (FIG. 4A) Pictures of one each of wild-type (WT) and EKLFK74R (Kin) mice at 3 months of age. (FIG. 4B) Body weights of EKLF K74R(Kin) and WT mice at 3, 6, 12, 18 and 24 months of age. The canonicaldiurnal metabolic parameters, including food (FIG. 4C) and water (FIG.4D) intake, were measured for WT and EKLF K74R (Kin) mice at 3 and 24months of age, respectively. The data are means±SEM. Statisticalsignificance was assessed by two-tailed Student's t-test.

FIGS. 5A-5D show comparisons of whole-body energy expenditures ofwild-type (WT) and EKLF K74R (Kin) mice. The canonical diurnal metabolicparameters measured for the 3-month and 24-month old mice include VO₂(FIG. 5A), VCO₂ (FIG. 5B), heat production (FIG. 5C) and respiratoryexchange ratio (RER) (FIG. 5D). The data are presented as means±SEM.Statistical significance was assessed by the two-tailed Student'st-test.

FIGS. 6A-6C show measurements of the concentrations of fasting bloodglucose (FIG. 6A) and insulin (FIG. 6B), and the glucose tolerance test(FIG. 6C) for wild-type (WT; circles) and EKLF K74R mice (Kin; squares).The data are presented as means±SEM, with n=3 to 9 in each group.Statistical significance was assessed by the two-tailed Student'st-test.

FIGS. 7A and 7B show comparisons of physical characteristics ofwild-type (WT) and EKLF K74R (Kin) mice at 3-month and 24-month of age.(FIG. 7A) Results of the grip strength test are shown. (FIG. 7B) Resultsof the rotarod performance test are shown. Data are presented asmean±SEM (n=20 each). p-value(s) indicates the significance of thegenotype effect in two-way repeated measures ANOVA. The data arepresented as means±SEM. Statistical significance was assessed bytwo-tailed Student's t-test.

FIG. 8 shows an assessment of osteoporosis in male mice. The trabecularbones of wild-type (WT; left panels) and EKLF K74R (Kin; right panels)mice of the age of 3 months (top panels) or 24 months (bottom panels)were analyzed by high-resolution micro-computed tomography (mCT)imaging. n=3−6.

FIGS. 9A and 9B show MicroPET images of 24-month old wild-type (WT) andEKLF K74R (Tg) mice. (FIG. 9A) MicroPET images are shown of miceadministered with 100 Ci of 18F-FDG and scanned for 0.5 hr afterinjection. The white arrows indicate the tumors in liver, pancreas andspleen of wild-type mice but not EKLF K74R mice (Kin). (FIG. 9B) A tablesummarizing cancer occurrence in 2 out of 3 WT mice, but none in the 3Kin mice, as examined after body dissection.

FIGS. 10A and 10B show the anti-carcinogenesis capability of the EKLFK74R mice. (FIG. 10A) Representative photos of lungs from wild-type (WT)and EKLF K74R (Kin) mice 14 days after injection of the B16F10 melanomacells are shown. The lungs of all 3 injected WT mice developed tumors onthe lungs (left panel), while none of the 3 Kin mice had tumors on theirlungs (right panel). Scale bars are 5 mm. (FIG. 10B) Bar diagram of thecomparison of tumor.

DETAILED DESCRIPTION OF THE INVENTION

The practice of the present invention will employ, unless indicatedspecifically to the contrary, conventional methods of molecular biologyand recombinant DNA techniques within the skill of the art, many ofwhich are described below for the purpose of illustration. Suchtechniques are explained fully in the literature. See, e.g., Sambrook,et al., Molecular Cloning: A Laboratory Manual (3r^(d) Edition, 2000);DNA Cloning: A Practical Approach, vol. I & II (D. Glover, ed.);Oligonucleotide Synthesis (N. Gait, ed., 1984); OligonucleotideSynthesis: Methods and Applications (P. Herdewijn, ed., 2004); NucleicAcid Hybridization (B. Hames & S. Higgins, eds., 1985); Nucleic AcidHybridization: Modern Applications (Buzdin and Lukyanov, eds., 2009);Transcription and Translation (B. Hames & S. Higgins, eds., 1984);Animal Cell Culture (R. Freshney, ed., 1986); Freshney, R. I. (2005)Culture of Animal Cells, a Manual of Basic Technique, 5^(th) Ed. HobokenN.J., John Wiley & Sons; B. Perbal, A Practical Guide to MolecularCloning (3^(rd) Edition 2010); Farrell, R., RNA Methodologies: ALaboratory Guide for Isolation and Characterization (3^(rd) Edition2005). Poly(ethylene glycol), Chemistry and Biological Applications,ACS, Washington, 1997; Veronese, F., and J. M. Harris, Eds., Peptide andprotein PEGylation, Advanced Drug Delivery Reviews, 54(4) 453-609(2002); Zalipsky, S., et al., “Use of functionalized Poly(EthyleneGlycols) for modification of polypeptides” in Polyethylene GlycolChemistry: Biotechnical and Biomedical Applications.

Definitions

For convenience, certain terms employed in the context of the presentdisclosure are collected here. Unless defined otherwise, all technicaland scientific terms used herein have the same meaning as commonlyunderstood by one of the ordinary skill in the art to which thisinvention belongs.

“Enhancing longevity” “increasing longevity” and “life-extension” areused interchangeably herein and refer to a delay of the normal agingprocess and/or prolonging the lifespan of an animal, e.g., an animalsuffering from a life-threatening disorder (e.g., a cancer or tumor).Preferably, the longevity is due to an extension of the mature lifephase, as opposed to an extension of the immature life phase, and isresulted from being treated by the present method.

“Enhancing health span” refers to a delay in the onset or severity ofphysical deterioration, diseases, or disorders associated with agingEnhanced health span also refers to a reduction or reduced amount ofphysical deterioration, diseases, or disorders normally associated withaging, e.g., at a particular age.

As used herein, the term “allele” refers to one specific form of a genewithin a cell or within a population, the specific form which may differfrom other forms of the same gene in the sequence of at least one, andfrequently more than one, variant sites within the sequence of the gene.The sequences at these variant sites that differ between differentalleles are termed “variances”, “polymorphisms”, or “mutations”. When asubject has two identical alleles of a gene, the subject is said to behomozygous for that gene or allele. When a subject has two differentalleles of a gene, the subject is said to be heterozygous for that gene.Alleles of a specific gene can differ from each other in a singlenucleotide or several nucleotides, and can include substitutions,deletions, and insertions of nucleotides. An allele of a gene can alsobe a form of a gene containing a mutation.

As used herein, the term “expression” is intended to refer totranscription of a gene when a condition is met, resulting in thegeneration of mRNA and usually encoded protein. Expression can beachieved or performed naturally by the cell (i.e., without artificiallyintervention) or may be achieved or performed artificially (i.e., withthe involvement of artificially intervention, such as by the use ofpromoters regulated by the use of a chemical agent). The expression mayalso be initiated by a recombination event triggered by a site-specificrecombinase, such as by Cre-mediated recombination. Expression may bemeasured by measuring mRNA transcribed from the gene or by measuringprotein encoded by the gene.

The term “nucleic acid” refers to polynucleotides such asdeoxyribonucleic acid (DNA) and where appropriate, ribonucleic acid(RNA). Nucleic acids include but are not limited to single-stranded anddouble-stranded polynucleotides. Illustrative polynucleotides includeDNA, single-stranded DNA, cDNA, and mRNA. The term also includes,analogs of either DNA or RNA made from nucleotide analogs, and asapplicable, single (sense or antisense) and double-strandedpolynucleotides. The term further includes modified polynucleotides,including modified DNA and modified RNA, e.g., DNA and RNA comprisingone or more unnatural nucleotide or nucleoside. The terms “nucleic acid”and “polynucleotide” are used interchangeably herein to refer todeoxyribonucleotides or ribonucleotides and polymers thereof in eithersingle- or double-stranded form. The term encompasses nucleic acidscontaining known nucleotide analogs or modified backbone residues orlinkages, which are synthetic, naturally occurring, and non-naturallyoccurring, and/or which have similar binding properties as the referencenucleic acid, and/or which are metabolized in a manner similar to thereference nucleotides. Examples of such analogs include, withoutlimitation, phosphorothioates, phosphoramidates, methyl phosphonates,chiral-methyl phosphonates, 2-O-methyl ribonucleotides, peptide-nucleicacids (PNAs).

Unless otherwise indicated, a particular nucleic acid sequence alsoencompasses conservatively modified variants thereof (e.g., degeneratecodon substitutions) and complementary sequences, as well as thesequence explicitly indicated. Specifically, degenerate codonsubstitutions may be achieved by generating sequences in which the thirdposition of one or more selected (or all) codons is substituted withmixed-base and/or deoxyinosine residues (Batzer et al., Nucleic AcidRes. 19:5081 (1991); Ohtsuka et al., J. Biol. Chem. 260:2605-2608(1985); Rossolini et al., Mol. Cell. Probes 8:91-98 (1994)).

An “isolated” nucleic acid molecule is a nucleic acid molecule withwhich it is ordinarily associated in the natural source of the nucleicacid. An isolated nucleic acid molecule is other than in the form orsetting in which it is found in nature. Isolated nucleic acid moleculestherefore are distinguished from the nucleic acid molecule as it existsin nature cells.

The term “vector” refers to a nucleic acid molecule capable oftransporting another nucleic acid to which it has been linked. The term“expression vector” refers to a vector comprising a promoter operablylinker to a nucleic acid in a manner allowing expression of the operablylinked nucleic acid. Vectors or expression vectors as used herein thusinclude plasmids or phages capable of synthesizing the subject proteinencoded by the respective recombinant gene carried by the vector.Vectors or expression vectors also include viral-based vectors capableof introducing a nucleic acid into a cell, e.g., a mammalian cell.Certain vectors are capable of autonomous replication and/or expressionof nucleic acids to which they are linked.

In the present disclosure, nucleic acid is “operably linked” when it isplaced into a functional relationship with another nucleic acidsequence. For example, a promoter is operably linked to a codingsequence if it affects the transcription of the sequence; or a ribosomebinding site is operably linked to a coding sequence if it is positionedso as to facilitate translation. In general, “operably linked” meansthat the DNA sequences being linked are contiguous, and in readingphase. However, enhancers do not have to be contiguous. Linking isaccomplished by ligation at convenient restriction sites, if such sitesdo not exist, the synthetic oligonucleotide adaptors or linkers are usedin accordance with conventional practice.

The term “transfection” refers to the introduction of nucleic acid,e.g., an expression vector, into a recipient cell by nucleic acidmediated gene transfer. “Transformation” refers to a process in which acell's genotype is changed as the result of the cellular uptake ofexogenous DNA or RNA, and the transformed cell expresses a desiredheterologous protein.

As used herein the term “transgene” refers to a nucleic acid sequencewhich is partly or entirely heterologous, i.e., foreign, to thetransgenic animal or cell into which it is introduced, or is homologousto an endogenous gene of the transgenic animal or cell into which it isintroduced, but which is designed to be inserted, or is inserted, intothe animal's genome in such a way that the genome of the cell to whichit is inserted is altered. A transgene can be operably linked to one ormore transcriptional regulatory sequences and any other nucleic acid,such as introns, that may be necessary for optimal expression of aselected nucleic acid. Therefore, the term “transgenic” is used hereinas an adjective to describe the property of an animal or a construct, ofharboring a transgene. For example, “a transgenic animal” is a non-humananimal, preferably a non-human mammal, more preferably, a rodent, inwhich one or more of the cells of the animal contain heterologousnucleic acid introduced by way of human intervention, such as bytransgenic techniques well known in the art, including gene knock-intechniques. The nucleic acid is introduced into the cell, directly orindirectly by introduction into a precursor of the cell, via deliberategenetic manipulation, such as by microinjection or by infection with arecombinant virus. Transgenic animals include, but are not limited to,knock-in animals.

A “knock-in (Kin)” refers to the targeted insertion of a transgene in ahost cell genome that results in expression of the transgene. “Knock-in”transgenics can comprise a heterozygous knock-in of a transgene. Incertain embodiments, a “knock-in” results in the replacement of anendogenous gene (or portion thereof) with an exogenous gene (or portionthereof), e.g., resulting in the targeted mutation of one or bothalleles. “Knock-in” also encompasses expression of a transgene byexposing the animal to a substance that promotes such expression, byintroducing an enzyme that promotes recombination at the site oftargeted insertion (e.g., Cre in Cre-lox system), or by some othermethod.

“Homozygous” state means a genetic condition existing when the samealleles reside at corresponding loci on homologous chromosomes. Incontrast, “heterozygous” state means a genetic condition existing whendifferent alleles reside at corresponding loci on homologouschromosomes.

The term “mammal” refers to all members of the class Mammalia, includinghumans, primates, domestic and farm animals, such as rabbit, pig, sheep,and cattle; as well as zoo, sports or pet animals; and rodents, such asmouse and rat. The term “non-human mammal” refers to all members of theclass Mammalis except human.

The term “treatment” as used herein is intended to mean obtaining adesired pharmacological and/or physiologic effect, e.g., delaying orinhibiting cancer occurrence, growth, or metastasis, or amelioratingischemic injury to an organ (e.g., brain). The effect may beprophylactic in terms of completely or partially preventing orinhibiting occurrence of a disease or symptom thereof and/or therapeuticin terms of a partial or complete cure for a disease and/or adverseeffect attributable to the disease. “Treatment” as used herein includespreventative (e.g., prophylactic), curative or palliative treatment of adisease in a mammal, particularly human; and includes: (1) preventative(e.g., prophylactic), curative or palliative treatment of a disease orcondition (e.g., a cancer or heart failure) from occurring in anindividual who may be pre-disposed to the disease but has not yet beendiagnosed as having it; (2) inhibiting a disease (e.g., by arresting itsdevelopment); or (3) relieving a disease (e.g., reducing symptomsassociated with the disease).

The term “administered”, “administering” or “administration” are usedinterchangeably herein to refer a mode of delivery, including, withoutlimitation, intraveneously, intramuscularly, intraperitoneally,intraarterially, intracranially, or subcutaneously administering anagent (e.g., a compound or a composition) of the present invention.

The term “an effective amount” as used herein refers to an amounteffective, at dosages, and for periods of time necessary, to achieve thedesired result with respect to the treatment of a disease or condition,such as aging. For example, in the treatment of a cancer, an agent(i.e., a compound, a polypeptide, or a polynucleic acid encoding atherapeutic polypeptide) which decreases, inhibits, prevents, delays orsuppresses or arrests any symptoms of the cancer would be effective. Aneffective amount of an agent is not required to cure a disease orcondition but will provide a treatment for a disease or condition suchthat the onset of the disease or condition is delayed, hindered orprevented, or the disease or condition symptoms are ameliorated. Theeffective amount may be divided into one, two or more doses in asuitable form to be administered at one, two or more times throughout adesignated time period.

The term “subject” refers to an animal including the human species thatis treatable with the method of the present invention. The term“subject” intended to refer to both the male and female gender unlessone gender is specifically indicated. Accordingly, the term “subject”comprises any mammal which may benefit from the treatment method of thepresent disclosure.

The term “cellular proliferative disorder,” “tumor,” and “cancer ” areused interchangeably herein, and is intended to mean any disordercharacterized by deregulated or uncontrolled, autonomous cell growth,including malignant and non-malignant growth, lack of differentiationand ability to invade local tissues and metastasize. Examples of thisdisorder include, but are not limited to, carcinoma, lymphoma, blastoma,sarcoma, and leukemia or lymphoid malignancies. More particular examplesof such disorders include, but are not limited to, liver cancer, coloncancer, breast cancer, prostate cancer, hepatocellular carcinoma,melanoma, lung cancer, glioblastoma, brain tumor, hematopoeiticmalignancies, retinoblastoma, renal cell carcinoma, head and neckcancer, cervical cancer, pancreatic cancer, esophageal cancer, andsquama cell carcinoma.

The singular forms “a”, “and”, and “the” are used herein to includeplural referents unless the context clearly dictates otherwise.

A “decreased” or “reduced” amount is typically a “statisticallysignificant” amount, and may include, for example, a 5%, 6%, 7%, 8%, 9%,10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18% , 19%, 20%, 25%, 30%, 35%,40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%decrease (including all integers and ranges in between) relative to acontrol. Other examples of comparisons and “statistically significant”amounts are described herein. “Decrease,” as used herein, can refer to“inhibit,” “reduce,” “curb,” “abate,” “diminish,” “lessen,” or “lower.”

A “increased” or “enhanced” amount is typically a “statisticallysignificant” amount, and may include, for example, a 5%, 6%, 7%, 8%, 9%,10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18% , 19%, 20%, 25%, 30%, 35%,40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%increase. An increased or enhanced amount may also include a 2-fold, 3,fold, 4 fold, 5 fold, 6 fold, 7 fold, 8-fold, 9-fold, 10 fold, 20-fold,30 fold, 40 fold, 50 fold, 60 fold 70 fold, 80-fold, 90-fold, 100-fold,200-fold, 300-fold, 400-fold, 500-fold, 1,000-fold, 10,000-fold, orgreater than 10,000-fold increase (including all integers and ranges inbetween) relative to a control. Other examples of comparisons and“statistically significant” amounts are described herein. “Increase,” asused herein, can refer to “agonize,” “enhance,” “inflate,” “escalate,”expand,” “augment,” “enlarge,” or “raise.”

The terms “polypeptide” and “protein” are used interchangeably herein torefer to a polymer of amino acid residues and to variants and syntheticanalogues of the same. Thus, these terms apply to amino acid polymers inwhich one or more amino acid residues are synthetic non-naturallyoccurring amino acids, such as a chemical analogue of a correspondingnaturally occurring amino acid, as well as to naturally-occurring aminoacid polymers. The polypeptides described herein are not limited to aspecific length of the product; thus, peptides, oligopeptides, andproteins are included within the definition of polypeptide, and suchterms may be used interchangeably herein unless specifically indicatedotherwise. The polypeptides described herein may also comprisepost-expression modifications, such as glycosylations, acetylations,phosphorylations and the like, as well as other modifications known inthe art, both naturally occurring and non-naturally occurring. Apolypeptide may be an entire protein, or a subsequence, fragment,variant, or derivative thereof.

The term “similar” as used herein, when referring to properties,characteristics, actions, or activities that can be measured and/orquantified, refers to the absence of a detectable and/or a statisticallysignificant difference.

The term “wild-type” refers to a gene or gene product that has thecharacteristics of that gene or gene product when isolated from anaturally-occurring source. A wild-type gene or gene product (e.g., apolypeptide) is that which is most frequently observed in a populationand is thus arbitrarily designed the “normal” or “wild-type” form of thegene.

A “control animal,” as used herein, refers to an animal that closelyresembles the experimental animal, e.g. a genetically modified animalthat expresses modified EKLF polypeptide, without possessing theexperimental feature, e.g. expression of a modified EKLF polypeptide.For a given experiment or experimental comparison, one of ordinary skillin the art will be able to select an appropriate control animaldepending on considerations that can include, but are not limited to,the nature of the experiment or comparison, the species and age of thegenetically modified animal, and experimental feasibility Unlessotherwise stated, the control animal does not comprise a modification atthe EKLF locus and does not express modified EKLF polypeptide. In somecases, the control animal may be a littermate of the same gender as thegenetically modified animal.

An “aged” animal, as used herein, refers to an adult animal thatdisplays at least one phenotype associated with normal ageing. The exactage that an animal will be considered “aged” depends on the speciesand/or the strain of the animal, as well as the phenotype in question,and can readily be determined by those of skill in the art.

“Homology” refers to the percentage number of amino acids that areidentical or constitute conservative substitutions. Homology may bedetermined using sequence comparison programs such as GAP (Deveraux etal., 1984, Nucleic Acids Research 12, 387-395), which is incorporatedherein by reference. In this way sequences of a similar or substantiallydifferent length to those cited herein could be compared by insertion ofgaps into the alignment, such gaps being determined, for example, by thecomparison algorithm used by GAP.

By “statistically significant”, it is meant that the result was unlikelyto have occurred by chance. Statistical significance can be determinedby any method known in the art. Commonly used measures of significanceinclude the p-value, which is the frequency or probability with whichthe observed event would occur, if the null hypothesis were true. If theobtained p-value is smaller than the significance level, then the nullhypothesis is rejected. In simple cases, the significance level isdefined at a p-value of 0.05 or less. The term “significant” encompassesand includes the term “statistically significant.”

The recitations “sequence identity” or, for example, comprising a“sequence 50% identical to,” as used herein, refer to the extent thatsequences are identical on a nucleotide-by-nucleotide basis or an aminoacid-by-amino acid basis over a window of comparison. Thus, a“percentage of sequence identity” may be calculated by comparing twooptimally aligned sequences over the window of comparison, determiningthe number of positions at which the identical nucleic acid base (e.g.,A, T, C, G, I) or the identical amino acid residue (e.g., Ala, Pro, Ser,Thr, Gly, Val, Leu, Ile, Phe, Tyr, Trp, Lys, Arg, His, Asp, Glu, Asn,Gln, Cys and Met) occurs in both sequences to yield the number ofmatched positions, dividing the number of matched positions by the totalnumber of positions in the window of comparison (i.e., the window size),and multiplying the result by 100 to yield the percentage of sequenceidentity.

Terms used to describe sequence relationships between two or morepolypeptides include “reference sequence,” “comparison window,”“sequence identity,” “percentage of sequence identity” and “substantialidentity.” A “reference sequence” is at least 12 but frequently 15 to 18and often at least 25 monomer units, inclusive of nucleotides and aminoacid residues, in length. Because two polypeptides may each comprise (1)a sequence (i.e., only a portion of the complete polypeptides sequence)that is similar between the two polypeptides, and (2) a sequence that isdivergent between the two polypeptides, sequence comparisons between two(or more) polypeptides are typically performed by comparing sequences ofthe two polypeptides over a “comparison window” to identify and comparelocal regions of sequence similarity. A “comparison window” refers to aconceptual segment of at least 6 contiguous positions, usually about 50to about 100, more usually about 100 to about 150 in which a sequence iscompared to a reference sequence of the same number of contiguouspositions after the two sequences are optimally aligned. The comparisonwindow may comprise additions or deletions (i.e., gaps) of about 20% orless as compared to the reference sequence (which does not compriseadditions or deletions) for optimal alignment of the two sequences.Optimal alignment of sequences for aligning a comparison window may beconducted by computerized implementations of algorithms (GAP, BESTFIT,FASTA, and TFASTA in the Wisconsin Genetics Software Package Release7.0, Genetics Computer Group, 575 Science Drive Madison, Wis., USA) orby inspection and the best alignment (i.e., resulting in the highestpercentage homology over the comparison window) generated by any of thevarious methods selected. Reference also may be made to the BLAST familyof programs as for example disclosed by Altschul et al., 1997, Nucl.Acids Res. 25:3389. A detailed discussion of sequence analysis can befound in Unit 19.3 of Ausubel et al., “Current Protocols in MolecularBiology,” John Wiley & Sons Inc, 1994-1998, Chapter 15.

Calculations of sequence similarity or sequence identity betweensequences (the terms are used interchangeably herein) can be performedas follows. To determine the percent identity of two amino acidsequences, or of two nucleic acid sequences, the sequences can bealigned for optimal comparison purposes (e.g., gaps can be introduced inone or both of a first and a second amino acid or nucleic acid sequencefor optimal alignment and non-homologous sequences can be disregardedfor comparison purposes). In certain embodiments, the length of areference sequence aligned for comparison purposes is at least 30%,preferably at least 40%, more preferably at least 50%, 60%, and evenmore preferably at least 70%, 80%, 90%, 100% of the length of thereference sequence. The amino acid residues or nucleotides atcorresponding amino acid positions or nucleotide positions are thencompared. When a position in the first sequence is occupied by the sameamino acid residue or nucleotide as the corresponding position in thesecond sequence, then the molecules are identical at that position.

The percent identity between the two sequences is a function of thenumber of identical positions shared by the sequences, taking intoaccount the number of gaps, and the length of each gap, which need to beintroduced for optimal alignment of the two sequences.

The comparison of sequences and determination of percent identitybetween two sequences can be accomplished using a mathematicalalgorithm. In a preferred embodiment, the percent identity between twoamino acid sequences is determined using the Needleman and Wunsch,(1970, J. Mol. Biol. 48: 444-453) algorithm which has been incorporatedinto the GAP program in the GCG software package, using either a Blossum62 matrix or a PAM250 matrix, and a gap weight of 16, 14, 12, 10, 8, 6,or 4 and a length weight of 1, 2, 3, 4, 5, or 6. In yet anotherpreferred embodiment, the percent identity between two nucleotidesequences is determined using the GAP program in the GCG softwarepackage, using a NWSgapdna.CMP matrix and a gap weight of 40, 50, 60,70, or 80 and a length weight of 1, 2, 3, 4, 5, or 6. A particularlypreferred set of parameters (and the one that should be used unlessotherwise specified) are a Blossum 62 scoring matrix with a gap penaltyof 12, a gap extend penalty of 4, and a frameshift gap penalty of 5. Thepercent identity between two amino acid or nucleotide sequences can alsobe determined using the algorithm of E. Meyers and W. Miller (1989,Cabios, 4: 11-17) which has been incorporated into the ALIGN program(version 2.0), using a PAM120 weight residue table, a gap length penaltyof 12 and a gap penalty of 4.

The nucleic acid and protein sequences described herein can be used as a“query sequence” to perform a search against public databases to, forexample, identify other family members or related sequences. Suchsearches can be performed using the NBLAST and XBLAST programs (version2.0) of Altschul, et al., (1990, J. Mol. Biol, 215: 403-10). BLASTnucleotide searches can be performed with the NBLAST program, score=100,wordlength=12 to obtain nucleotide sequences homologous to nucleic acidmolecules of the invention. BLAST protein searches can be performed withthe XBLAST program, score=50, wordlength=3 to obtain amino acidsequences homologous to protein molecules of the invention. To obtaingapped alignments for comparison purposes, Gapped BLAST can be utilizedas described in Altschul et al., (1997, Nucleic Acids Res, 25:3389-3402). When utilizing BLAST and Gapped BLAST programs, the defaultparameters of the respective programs (e.g., XBLAST and NBLAST) can beused.

The term “antibody” herein is used in the broadest sense andspecifically covers intact monoclonal antibodies, polyclonal antibodies,multispecific antibodies (e.g. bispecific antibodies) formed from atleast two intact antibodies, and antibody fragments, so long as theyexhibit the desired antigen-binding activity. “Antibody fragments”comprise a portion of an intact antibody, preferably comprising theantigen-binding or variable region thereof. Examples of antibodyfragments include Fab, Fab′, F(ab′)₂, scFv and Fv fragments; diabodies;nanobodies; linear antibodies; single-chain antibody molecules; andmultispecific antibodies formed from antibody fragment(s).

Genetically Modified Animals

The present disclosure is based, in part, on the development of aknock-in animal, e.g. a knock-in mouse, that serves as an animal modelfor longevity, anti-aging, anti-carcinogenesis, and/or anti-metastasis,wherein one or both of the endogenous Erythroid Kruppel-like factor(EKLF) gene alleles are modified to encode a modified EKLF polypeptide,including any of those specifically described herein. The expression ofthe modified EKLF polypeptide in the genetically modified animal leadsto an enhanced lifespan and/or health span of the animal, and/or thesuppression or inhibition of tumor formation and/or the metastasis ofcancerous cells. Therefore, the introduction of the modified EKLF alleleprovides a means for increasing the lifespan or health span of asubject, a means for treating a cellular proliferative disorder, e.g.,inhibiting tumor formation or tumor metastasis, as well as a means forscreening candidate agents suitable as anti-aging and/or anti-tumoragents.

Particular embodiments contemplate that the genetically modifiednon-human animal model developed herein is a valuable tool to studyaging, longevity, and progression and treatment of a cellularproliferative disorder (e.g., cancer). This animal model is particularlyadvantageous in that it does not exhibit impaired or modified metabolismas compared to normal animals. In particular, the non-human geneticallymodified animal model of the present disclosure finds utilities instudying aging, longevity, and screening candidates as anti-aging agentsas well as agents for the treatment or prevention of cancer, includingmetastatic cancer.

Particular embodiments are directed to a genetically modified animalthat comprises a nucleic acid (e.g., DNA) sequence that encodes amodified EKLF polypeptide. A “modified EKLF polypeptide” includes EKLFvariants having at least one amino acid modification as compared to awild-type EKLF protein, and fragments thereof having at least 100, 200,300, or 350 amino acids, that have at least 80%, 85%, 90%, 95%, 96%,97%, 98%, or 99% sequence identity to a wild-type EKLF protein.

Certain embodiments are directed to a genetically modified animal thatcomprises a nucleic acid sequence that encodes a modified EKLFpolypeptide, wherein the animal also comprises a nucleic acid sequencethat encodes a wild-type EKLF. Particular embodiments are directed to agenetically modified animal that comprises a nucleic acid (e.g., DNA)sequence that encodes a modified EKLF polypeptide, wherein the animaldoes not also comprises a nucleic acid sequence that encodes a wild-typeEKLF. In various embodiments, the animal expresses the modified EKLFpolypeptide and the endogenous EKLF polypeptide, while in someembodiments, the animal expresses only the modified EKLF polypeptide.

In some embodiments, the nucleic acid sequence encoding the modifiedEKLF is regulated by an endogenous EKLF gene promoter. Certainembodiments are directed to a genetically modified non-human animal thatexpresses a modified EKLF protein, wherein the genetically modifiedanimal comprises a nucleic acid sequence that encodes a modified EKLFprotein, wherein the EKLF protein is under the control of the endogenousEKLF promoter. Some embodiments are directed to a genetically modifiednon-human animal that expresses a modified EKLF protein, wherein thegenetically modified animal comprises a nucleic acid sequence (e.g.,DNA) that encodes a modified EKLF protein and an exogenous promoter,wherein the nucleic acid sequence that encodes the modified EKLF isoperably linked to or under control of the exogenous promoter. In someembodiments, the exogenous promoter is selected from promoters that thatdirect expression of the transgene in a constitutive manner, promotersthat direct the expression in a tissue specific manner, induciblepromoters e.g. Tet-On inducible promoters, and promoters that directexpression in a developmental or timing dependent manner. Certainembodiments are directed to a genetically modified non-human animal thatexpresses a modified EKLF protein, wherein the genetically modifiedanimal comprises a nucleic acid sequence that encodes a modified EKLFprotein, wherein the EKLF protein is under the control of the endogenousEKLF promoter. By “promoter” is meant a region of DNA that initiatestranscription of a particular gene. By “endogenous promoter” is meant apromoter that naturally directs expression of the gene of interest in acell or subject, i.e., a native promoter. In the case of knock-in mice,the expression of the modified gene may be directed by the endogenousmouse promoter for that gene.

Particular embodiments are directed to a non-human EKLF knock-in animal.As used herein, “knock-in animal” refers to a transgenic animalgenerated by a genetic engineering method that involves the insertion ofa DNA sequence, e.g., a cDNA sequence, at a particular locus in anorganism's chromosome. The insert is flanked by DNA from a non-criticallocus, and homologous recombination allows the transgene to be targetedto that specific, non-critical integration site. The term “knock-in” isintended to include first generation animals as well as progeny thereofthat have the transgene in at least one allele thereof. In someembodiments, the insert comprises DNA that is targeted to the EKLF genelocus, or a fragment thereof, wherein the insert encodes a modified EKLFpolypeptide or a region or portion thereof. In some embodiments, theinsert is targeted to a protein encoding region of the EKLF gene locus.In certain embodiments, the insert encodes a modified EKLF polypeptideand a modified EKLF promoter.

“EKLF knock-in” as used herein, refers to a transgenic non-human animalwhereby nucleic acid that encodes a modified EKLF polypeptide, orportion or region thereof, has been inserted into the EKLF locus, e.g.,to replace the nucleic acid of the animal that encodes the correspondingwild-type EKLF polypeptide, or portion or region thereof In someembodiments, the knock-in animal is heterozygous, comprising one copy ofthe endogenous EKLF gene and one copy of the modified knock-in EKLFgene. In particular embodiments, the genetically modified animal is anEKLF knock-in mouse. In certain embodiments, the knock-in animal ishomozygous, comprising two copies of the modified knock-in EKLF gene.

In certain embodiments, the non-human animal is genetically modified bythe replacement of an endogenous EKLF genomic sequence (or a portionthereof), at an endogenous EKLF locus, with a modified EKLF genomicsequence (or a portion thereof) to form a modified locus, wherein themodified EKLF genomic sequence comprises at least one modifiedprotein-coding exon. In some embodiments, the replacement comprises amodified genomic fragment comprising at least two protein-coding exonsof EKLF. In some embodiments, the replacement comprises a modifiedgenomic fragment that comprises at least three protein-coding exons ofmodified EKLF. In particular embodiments, the non-human animal isgenetically modified by the replacement of the endogenous exon 2 of theEKLF gene with a modified exon 2 of the EKLF gene (or portion thereof).In particular embodiments, a region of the endogenous EKLF genomicsequence that encodes a sumoylation site or a phosphorylation site ofthe EKLF protein is replaced by a modified EKLF genomic sequence.

Particular embodiments are directed to genetically modified non-humananimals that comprise a modified EKLF locus that encodes an EKLFpolypeptide comprising a modification of one or more amino acidscompared to the endogenous, wild-type EKLF, including any of thosedescribed herein. In particular embodiments, the modified EKLFpolypeptide comprises a modification that inhibits its sumoylation. Theorganisms are generally able to pass the modification to progeny, i.e.,through germline transmission. In some embodiments, the geneticallymodified non-human animals are offspring of a parent comprising amodified EKLF locus that encodes a modified EKLF polypeptide. In someembodiments, the offspring are homozygous for the modified EKLF locus.In certain embodiments, the offspring are heterozygous for the modifiedEKLF locus.

Certain embodiments are directed to genetically modified non-humananimals that comprise a modified EKLF locus that encodes an EKLFpolypeptide comprising a modification of one or more amino acidscompared to the endogenous, wild-type EKLF, and further comprise amodification at one or more additional loci. In some embodiments, thegenetically modified animal comprises modifications at one additionallocus, two additional loci, three additional loci, four additional loci,five additional loci, six additional loci, seven additional loci, eightadditional loci, nine additional loci, ten additional loci, or more thanten additional loci. In some embodiments, the modification of theadditional locus is a gene knockout, gene knock-in, or the insertion ofan exogenous gene.

Particular embodiments are directed to a non-human EKLF knock-in animalthat is crossed with a genetically modified animal comprising amodification of at least one additional locus. Certain embodiments aredirected to offspring that express a modified EKLF polypeptide that arethe product of a cross between an EKLF knock-in animal and geneticallymodified animal comprising a modification of at least one additional,non-EKLF locus. Genetically modified animals are known in the art, andmay include transgenic animals with inducible expression of exogenouspeptides, inducible knockout animal models, e.g. CRE-loxP, inducibleknock-in animals, e.g. crisper/Cas. In certain embodiments, the EKLFknock-in is crossed with a transgenic animal, e.g., a knock-in animal,and/or a knockout animal. In some embodiments, the EKLF knock-in animalis crossed with a genetically modified animal that models a disease,e.g. cancer, or aspects of longevity, e.g. S6K1 knockout.

In some embodiments, the genetically modified non-human animal may beselected from a group consisting of a mouse, rat, rabbit, pig, bovine(e.g., cow, bull, buffalo), deer, sheep, goat, chicken, cat, dog,ferret, primate (e.g., marmoset, rhesus monkey). In certain embodiments,the non-human animal is a mammal, e.g., a non-human mammal. In certainembodiments, the non-human animal is a small mammal, e.g., of thesuperfamily Muroidea. In some embodiments, the genetically modifiedanimal is a rodent. In some embodiments, the rodent is selected from amouse, a rat, and a hamster. In some embodiments, the rodent is selectedfrom the superfamily Muroidea. In one embodiment, the geneticallymodified animal is from a family selected from Calomyscidae (e.g.,mouse-like hamsters), Cricetidae (e.g., hamster, New World rats andmice, voles), Muridae (true mice and rats, gerbils, spiny mice, crestedrats), Nesomyidae (climbing mice, rock mice, with-tailed rats, Malagasyrats and mice), Platacanthomyidae (e.g., spiny dormice), and Spalacidae(e.g., mole rates, bamboo rats, and zokors). In some embodiments, thegenetically modified rodent is selected from a true mouse or rat (familyMuridae), a gerbil, a spiny mouse, and a crested rat. In one embodiment,the genetically modified mouse is from a member of the family Muridae.In one embodiment, the animal is a rodent. In a specific embodiment, therodent is selected from a mouse and a rat. In one embodiment, thenon-human animal is a mouse. In particular embodiments, the geneticallymodified non-human animal is an EKLF knock-in mouse.

In certain embodiments, the non-human animal is a rodent that is a mouseof a C57BL strain selected from C57BL/A, C57BL/An, C57BL/GrFa,C57BL/KaLwN, C57BL/6, C57BL/6J, C57BL/6ByJ, C57BL/6NJ, C57BL/10,C57BL/10ScSn, C57BL/10Cr, and C57BL/Ola. In another embodiment, themouse is a 129 strain selected from the group consisting of a strainthat is 129P1, 129P2, 129P3, 129X1, 129S1 (e.g., 129S1/SV, 129S1/SvIm),129S2, 129S4, 129S5, 12959/SvEvH, 129S6 (129/SvEvTac), 129S7, 129S8,129T1, 129T2 (see, e.g., Festing et al. (1999) Revised nomenclature forstrain 129 mice, Mammalian Genome 10:836, see also, Auerbach et al.(2000) Establishment and Chimera Analysis of 129/SvEv- andC57BL/6-Derived Mouse Embryonic Stem Cell Lines). In some embodiments,the genetically modified mouse is a mix of an aforementioned 129 strainand an aforementioned C57BL/6 strain. In another specific embodiment,the mouse is a mix of aforementioned 129 strains, or a mix ofaforementioned BL/6 strains. In some embodiments, the 129 strain of themix is a 129S6 (129/SvEvTac) strain. In another embodiment, the mouse isa BALB strain, e.g., BALB/c strain. In yet another embodiment, the mouseis a mix of a BALB strain and another aforementioned strain. In yetanother embodiment, the mouse is of a hybrid line (e.g., 50% BALB/c-50%12954/Sv; or 50% C57BL/6-50% 129; e.g., F1H4 cells, see, e.g., Auerbachet al. (2000)).

In certain embodiments, the non-human animal is a rat. In someembodiments, the rat is selected from a Wistar rat, an LEA strain, aSprague Dawley strain, a Fischer strain, F344, F6, and Dark Agouti. Insome embodiments, the rat strain is a mix of two or more strainsselected from the group consisting of Wistar, LEA, Sprague Dawley,Fischer, F344, F6, and Dark Agouti.

Although genetically modified cells are also provided that comprise themodifications described herein, in many aspects and embodiments, thegenetically modified non-human animals comprise the modification of theendogenous EKLF locus in the germline of the animal.

In various embodiments, the non-human animals are mammals. In certainembodiments, the mammals are rodents. Particular embodiments aredirected to rodents that comprise a modification of the EKLF gene at oneor both endogenous rodent EKLF loci. Methods are provided for makingrodents, e.g., mice, that comprise a replacement of an endogenous EKLFgene or fragment thereof (e.g., a fragment comprising one or more exons)with a modified EKLF gene, or fragment thereof, at one or both of theendogenous EKLF loci. Particular embodiments are directed to cells,tissues, and mice that comprise the modified EKLF gene, as well ascells, tissues, and mice that express human EKLF from an endogenousnon-human EKLF locus. Rodents that express a modified EKLF protein undercontrol of an endogenous rodent promoter are also provided.

Certain embodiments are directed to methods of generating a geneticallymodified knock-in animal that expresses a modified EKLF polypeptide,including but not limited to homozygotes that express the modified EKLFpolypeptide but not a wild-type EKLF polypeptide. Techniques andstrategies for generating knock-in animals, e.g. mice, are well known inthe art and are reviewed in (Doyle et al. 2012 Transgenic Res. 21(2):327-349; and Roebroek et al. Chapter 10 In: Hofker MEI, Deursen Jv,editors. Transgenic mouse: Methods and protocols. Humana Press; Totowa,N.J.: 2003. pp. xiiipp. 3741pp. 3187-3200).

In one such strategy, knock-in mice are generated in a two-stagedprocess that utilizes pluripotent embryonic stem (ES) cells as a vehiclewith which to translate experimental genetic manipulations intoMendelian inheritable traits in mice. In certain strategies, anembryonic stem cell isolated from a mouse is transfected with a DNAtargeting construct comprising regions of homology to an endogenous geneor chromosomal sequence, to facilitate homologous recombination. The DNAtargeting construct not only contains specific regions of gene homologybut also has a uniquely engineered mutation or sequence change such thatthe 1-to-1 replacement of the endogenous gene (or portion thereof) withsequence derived from the targeting construct following transfectioninto ES cells yields an allele in the genome of these cells containingthis new sequence variant. Targeted ES cell clones containing theappropriate genetic changes are transferred to the blastocoel cavitiesof 3.5 day blastocyst embryos. In turn, the embryos are transferred tosurrogate mothers where gestation is completed generating EScell-derived founder mice which have inherited the new sequence variant(i.e., the knock-in mutation), generating a gain-of-function allele atthis chosen genetic locus. One of skill in the art will recognize othersuitable strategies for generating knock-in animals, e.g. strategiesutilizing Cre-loxP system, and CRISPER/Cas9 technologies.

For the non-human animals where suitable genetically modifiable ES cellsare not readily available, other methods are employed to make anon-human animal comprising the genetic modification. Such methodsinclude, for example but not limited to, modifying a non-ES cell genome(e.g., a fibroblast or an induced pluripotent cell) and employingnuclear transfer to transfer the modified genome to a suitable cell,e.g., an oocyte, and gestating the modified cell (e.g., the modifiedoocyte) in a non-human animal under suitable conditions to form anembryo.

Some embodiments are directed to methods of generating a geneticallymodified animal that expresses a modified EKLF polypeptide utilizing theCre-loxP system. The Cre-loxP system has been used to modify theexpression of a selected gene or induce chromosomal rearrangements in acontrolled fashion, through the induction of a recombination in thegenome of isolated cells or transgenic animals. The system relies on anenzyme of the PI bacteriophage, Cre recombinase, that recognizes a short(34bp) asymmetric consensus sequence called loxP. When two suchsequences of the same orientation are located on a DNA molecule, theenzyme will catalyze the recombination between these two sites andexcise the intervening DNA segment. If the two loxP sequences arelocated on two different DNA molecules, such as on two chromosomes, thenCre will mediate an intermolecular recombination. The results of therecombination depends on the orientation of the loxP sites, for two loxsites on the same chromosome arm, inverted loxP sites will cause aninsertion, while a direct repeat of loxP sites will cause a deletionevent. Besides the Cre-loxP recombination system described herein, othersite-directed recombination systems can also be used to generatenon-human transgenic animal model as exemplified in the Examples of thepresent disclosure.

The genetically modified animals are screened and evaluated to selectthose animals having the phenotype of interest. Initial screening can beperformed using, for example, Southern blot analysis or PCR techniquesto analyze animal tissues to verify that integration of the transgenehas taken place. The level of mRNA expression of the transgene in thetissues of the transgenic animals can also be assessed using techniqueswhich include, but are not limited to, Northern blot analysis of tissuesamples obtained from the animal, in situ hybridization analysis, andreverse transcriptase-PCR (RT-PCR). Samples of the suitable tissues canbe evaluated immunocytochemically using antibodies specific for thetransgene. Alternative or additional methods for evaluating the presenceof the transgene include, but are not limited to, suitable biochemicalassays such as enzyme and/or immunological assays, histological stainsfor particular marker or enzyme activities, flow cytometric analysis,and the like. Analysis of the blood may also be useful to detect thepresence of the transgene product in the blood.

Particular embodiments are directed to methods of producing agenetically modified animal whereby the genetically modified animal isproduced from a pluripotent or totipotent cell (e.g., an ES cell). Incertain embodiments, the non-human animal is produced by employing anuclear injection step wherein a nucleic acid construct comprising themodified EKLF gene or a portion thereof (optionally with upstream and/ordownstream endogenous non-human regulatory sequences) is introduced bypronuclear injection. In some embodiments, the nucleic acid constructcomprises a genomic fragment that comprises at least one modifiedprotein-coding exons EKLF. In certain embodiments, the fragment containsportions of modified EKLF exon 2.

Some embodiments are directed to methods of generating a geneticallymodified animal that expresses a modified EKLF polypeptide comprisingthe steps of a) obtaining a vector comprising a polynucleotide encodinga modified EKLF polypeptide or a portion thereof; b) injecting thevector into an embryonic stem (ES) cell of a non-human animal; c)transferring an ES cell comprising the vector into a blastocyst embryo;d) transferring the blastocyst embryo into a surrogate mother wheregestation of the embryo is completed, thereby generating a founderanimal that comprises the polynucleotide encoding the modified EKLFpolypeptide, thereby generating the genetically modified animal. In someembodiments, the genetically modified animal is a knock-in animal,wherein the vector is a targeting vector comprising polynucleotideshomologous to endogenous DNA of the animal which flank thepolynucleotide that encodes the modified EKLF at the 3′ and 5′ ends. Inparticular embodiments, injecting the vector comprising polynucleotideshomologous to endogenous DNA of the animal into the ES cell results ininsertion of the polynucleotide into the genome of the ES cell throughhomologous recombination. In certain embodiments, the homologous DNA ishomologous to EKLF gene loci. In particular embodiments, the targetingvector further comprises selection cassette for use in identifying an EScell comprising the vector following injection of the vector into the EScell. In particular embodiments, the selection cassette is a PGK-gb2-neocassette. In certain embodiments, the selection cassette is flanked withloxP sites, and the method of generating a genetically modified animalfurther comprises the step of e) crossing an adult founder animal with atransgenic animal that expresses Cre in germline cells, and obtainingthe resulting progeny of the cross, thereby obtaining an animalexpressing a modified EKLF polypeptide that does not comprise aselection cassette in its genome.

Particular embodiments are directed to methods of generating a knock-inmouse expressing modified EKLF polypeptide, comprising the steps of a)obtaining a vector comprising a polynucleotide encoding a modified EKLFpolypeptide (or portion thereof) flanked on the 5′ and 3′ ends withpolynucleotides homologous to endogenous mouse EKLF gene; b) injectingthe vector into an mouse ES cell of a non-human animal, wherein thepolynucleotide encoding modified EKLF is inserted into the genome of theES cell at the EKLF gene loci through homologous recombination; c)transferring an ES cell comprising the vector into a 3.5 day old mouseblastocyst embryo; and d) transferring the blastocyst embryo into asurrogate mouse dam for the remainder of gestation, thereby generating afounder animal that comprises the polynucleotide encoding the modifiedEKLF polypeptide or portion thereof, thereby generating the geneticallyknock-in mouse. In certain embodiments, the vector further comprises aselection cassette. In some embodiments, the selection cassette is aPGK-gb2-neo cassette. In some embodiments, the vector comprises aselection cassette flanked by loxP sites, and the method furthercomprises the step of e) crossing an adult founder animal with atransgenic mouse that expresses Cre in germline cells, and obtaining theresulting progeny of the cross, thereby obtaining an EKLF knock-in mousethat does not comprise a selection cassette in its genome. In someembodiments, the vector comprises a polynucleotide encoding a EKLF witha lysine to arginine substitution at position 74 (K74R).

Once founder animals are produced, they can be bred, inbred, outbred, orcrossbred to produce colonies of the particular animal, includinghomozygous animals. Examples of such breeding strategies include, butare not limited to, outbreeding of founder animals with more than oneintegration site in order to establish separate lines; inbreeding ofseparate lines in order to produce transgenics, e.g. knock-in animals,that express the transgene at higher levels because of the effects ofadditive expression of each transgene; crossing of heterozygoustransgenic mice to produce mice homozygous for a given integration sitein order to both augment expression and eliminate the need for screeningof animals by DNA analysis; crossing of separate homozygous lines toproduce compound heterozygous or homozygous lines; breeding animals todifferent inbred genetic backgrounds so as to examine effects ofmodifying alleles on expression of the transgene and the effects ofexpression.

Particular embodiments are directed to a cell of (e.g., derived from orobtained from) a genetically modified animal that comprises DNA encodingmodified EKLF polypeptide at one or both EKLF loci. In some embodiments,the cell comprises DNA encoding modified EKLF polypeptide at one EKLFlocus. In certain embodiments, the cell comprises DNA encoding modifiedEKLF polypeptide at both EKLF loci. In some embodiments, the cell isisolated from the genetically modified animal. In particularembodiments, the cell expresses the modified EKLF polypeptide. Incertain embodiments, the cell does not express the modified EKLFpolypeptide. In certain embodiments, the cell has an ectodermal lineage.In some embodiments, the cell is selected from a Trichocyte,Keratinocyte, Gonadotrope, Corticotrope, Thyrotrope, Somatotrope,Lactotroph, Neuron, Glia, Schwann cell, Satellite glial cell, Chromaffincell, Parafollicular cell, Glomus cell, Melanocyte, Nevus cell, Merkelcell, Odontoblast, Cementoblast, Corneal keratocyte, Oligodendrocyte,Astrocyte, Ependymocytes, and Pinealocyte. In certain embodiments, thecell has an endodermal lineage. In some embodiments, the cell is aselected from a Type 1 Pneumocyte, Type 2 Pneumocyte, Club cell, Gobletcell, Gastric chief cell, Parietal cell, Foveolar cell, Enteroendocrinecell, G cell, Delta cell, Enterochromaffin-like cell, Enteroendocrinecell, Gastric inhibitory polypeptide S cell, Delta cell,Cholecystokinin, Goblet cell, Paneth cell, Enterocyte, Microfold cell,Hepatocyte, Hepatic stellate cell, Kupffer cell, Cholecystocyte,Centroacinar cell, Pancreatic stellate cell, Alpha cell, Beta cell,Delta cell, F cell, PP cell, Epsilon cell, Follicular cell, Parathyroidchief cell, Oxyphil cell, and Urothelial cell. In some embodiments, thecell has a mesodermal lineage. In some embodiments, the cell is selectedfrom an Osteoblast, Osteocyte, Chondroblast, Chondrocyte, Lipoblast,Adipocyte. Myoblast, Myocyte, Myosatellite cell, Tendon cell, Cardiacmuscle cell, Fibroblast, Fibrocyte, Interstitial cell of Cajal,Angioblast, Endothelial cell, Mesangial cell, Intraglomerular mesangialcell, Extraglomerular mesangial cell, Juxtaglomerular cell, Macula densacell, Stromal cell, Interstitial cell, Telocytes, Simple epithelialcell, Podocyte, Kidney proximal tubule brush border cell, Sertoli cell,Leydig cell, Granulosa cell, Peg cell, Germ cell, spermatozoon, ovum,Lymphoid, Lymphoblast, lymphocyte, Myeloid, Endothelial progenitor cell,Endothelial colony forming cell, Endothelial stem cell, Angioblast,Mesoangioblast, Pericyte, and Mural cell. In some embodiments, the cellis a stem cell. In certain embodiments, the cell is a totipotent stemcell, pluripotent stem cell, multipotent stem cell, oliopotent stemcell, or unipotent stem cell.

Particular embodiments are directed to a tissue of (e.g., derived fromor obtained from) a genetically modified animal that comprises amodified EKLF locus that encodes a modified EKLF polypeptide. In someembodiments, the tissue is isolated from the genetically modifiedanimal. In particular embodiments, the tissue comprises a modified EKLFlocus that encodes a modified EKLF polypeptide, wherein the tissueexpresses the modified EKLF polypeptide. In certain embodiments, thetissue comprises a modified EKLF locus that encodes a modified EKLFpolypeptide, wherein the tissue does not express the modified EKLFpolypeptide. In some embodiments, the tissue is a connective tissue, anervous tissue, an epithelial tissue, or a muscle tissue.

Certain embodiments are directed to an organ of (e.g., derived from orobtained from) a genetically modified animal that comprises a modifiedEKLF locus that encodes a modified EKLF polypeptide. In someembodiments, the organ is isolated from the genetically modified animal.In particular embodiments, the organ comprises a modified EKLF locusthat encodes a modified EKLF polypeptide, wherein the organ expressesthe modified EKLF polypeptide. In certain embodiments, the organcomprises a modified EKLF locus that encodes a modified EKLFpolypeptide, wherein the organ does not express the modified EKLFpolypeptide. In some embodiments, the organ is an organ of theIntegumentary system, Skeletal system, Muscular system, Lymphaticsystem, Respiratory system, Digestive system, Nervous system, Endocrinesystem, Cardiovascular system, Urinary system, or reproductive system.In some embodiments, the organ is skin, hair, nail, bone, joint,skeletal muscle, red bone marrow, thymus, lymphatic vessel, thoracicduct, spleen, lymph node, nasal cavity, pharynx, larynx, trachea,bronchus, lung, oral cavity, esophagus, liver, stomach, small intestine,large intestine, rectum, anus, brain, spinal cord, nerve, pineal gland,pituitary gland, thyroid gland, thymus, adrenal gland, pancreas, ovary,testis, heart, blood vessel, kidney, ureter, urinary bladder, urethra,prostate gland, penis, testis, scrotum, ductus deferens, Mammary glands,ovary, uterus, vagina, or uterine tube.

By “isolated” it is meant that the cell, tissue, or organ is removedfrom the animal. In some embodiments, the cell, tissue, or organ isliving, e.g. suitable for culture. In some embodiments, the cell,tissue, or organ is not considered live, e.g. fixed, and is suitable foranalysis.

Certain embodiments are directed to a construct for use in generating agenetically modified animal that expresses a modified EKLF polypeptide,e.g., a knock-in targeting vector. In particular embodiments, theconstruct comprises nucleic acid, e.g. DNA or cDNA, that comprises amodified sequence encoding at least a portion of a transcribed region ofthe modified EKLF gene. In some embodiments, the construct contains anucleic acid sequence comprising one or more modified EKLF exons. Inparticular embodiments, the construct comprises a selection marker, e.g.a PGK-gb2-neo template that encodes the neomycin/kanamycin resistancegene. In some embodiments, the construct comprises a selection markerthat is flanked by loxP. Particular embodiments are directed to aconstruct for use in generating knock-in mouse that comprises atargeting vector comprising a modified mouse EKLF exon 2 (or portionthereof) and a selectable marker, e.g., aPGK-gb2-neo selection cassette,flanked by two LoxP sites. In one embodiment, a knock-in targetingconstruct comprises: (i) at least a portion of a first EKLF genesequence; and (ii) at least a portion of a second EKLF gene sequencecomprising a modification. In one embodiment, a knock-in targetingconstruct comprises: (i) at least a portion of a first EKLF genesequence; (ii) a polyA sequence; (iii) a selectable marker (e.g.neomycin resistance) gene sequence; (iv) a promoter (e.g., PGK(phosphoglycerate kinase 1)) sequence; and (v) at least a portion of asecond EKLF gene sequence comprising a modification. In one embodiment,a knock-in targeting construct comprises: (i) at least a portion of afirst EKLF gene sequence; (ii) a loxP site; (iii) a polyA sequence; (iv)a selectable marker (e.g., neomycin resistance) gene sequence; (v) apromoter (e.g., PGK (phosphoglycerate kinase 1)) sequence; (vi) a loxPsite; and (vii) at least a portion of a second EKLF gene sequencecomprising a modification. In various embodiments, the first EKLF genesequence comprises at least a portion of exon 1 and intron 1 of EKLF,and the second EKLF gene sequence comprises at least a portion of exon2, intron 2 and exon 3 of EKLF, wherein exon 2 comprises a modificationcomprises a modified codon that encodes an amino acid residue notpresent in the endogenous EKLF protein, e.g., a modification of asumoylation site or phosphorylation site in the EKLF protein. Inparticular embodiments, the portion of the first EKLF sequence and theportion of the second EKLF sequence are of a length sufficient to allowhomologous recombination with an endogenous EKLF gene locus, e.g., atleast 20 nucleotides, at least 50 nucleotides, or at least 100nucleotides in length. In particular embodiments, the EKLF protein is amouse EKLF protein, and in certain embodiments, the modified codonencodes a modification at amino acid position 74. In particularembodiments, the EKLF protein is a human EKLF protein, and in certainembodiments, the modified codon encodes a modification at amino acidposition 54. In particular embodiments, the modified mouse exon 2encodes a region of mouse EKLF polypeptide comprising an amino acidmodification that prevents sumoylation or phosphorylation of the EKLFpolypeptide. In particular embodiments, the modified mouse exon 2encodes a region of mouse EKLF polypeptide comprising an amino acidsubstitution of lysine at position 74, e.g., substitution of lysine toarginine. In particular embodiments, the modification is any of thosedescribed herein.

In certain embodiments, the genetically modified animal expresses amodified EKLF polypeptide, wherein the modified EKLF polypeptide ismodified from a wild-type EKLF of the same species as the animal. Incertain embodiments, the genetically modified animal expresses amodified EKLF polypeptide, wherein the modified EKLF polypeptide ismodified from a wild-type EKLF of a different species from the animal.In some embodiments, the modified EKLF polypeptide is modified from amouse EKLF polypeptide (Accession: NP_034765.2; SEQ ID NO: 1). In someembodiments, the modified EKLF polypeptide is modified from a rat EKLFpolypeptide (Accession: NP_001100634.1; SEQ ID NO: 2). In someembodiments, the modified EKLF polypeptide is modified from a human EKLFpolypeptide (Accession: NP_006554.1; SEQ ID NO: 3). In some embodiments,the modified EKLF polypeptide is modified from a chimpanzee EKLFpolypeptide (Accession: XP_524128; SEQ ID NO: 4). In some embodiments,the modified EKLF polypeptide is modified from a rhesus monkey EKLFpolypeptide (Accession: NP_001181384 XP_001109612; SEQ ID NO: 5). Insome embodiments, the modified EKLF polypeptide is modified from a dogEKLF polypeptide (Accession: XP_542040; SEQ ID NO: 6). In someembodiments, the modified EKLF polypeptide is modified from a cattleEKLF polypeptide (Accession: NP_001073828 XP_001251865; SEQ ID NO: 7).In particular embodiments, a modified EKLF locus, or a portion comprisedin a vector described herein, is modified from a human EKLF genesequence (Accession ENSMUSG00000105610; SEQ ID NO:9) or a mouse EKLFgene sequence (Accession ENSMUSG00000054191; SEQ ID NO:10), or a relatedgene. Portions of these sequences may be present in vectors of thepresent invention.

In some embodiments, the genetically modified non-human animal expressesa modified EKLF polypeptide that comprises at least one amino acidmodification compared to wild-type EKLF. In particular embodiments, thetransgenic animal expresses a polypeptide comprising one or more aminoacid modifications as compared to a wild-type EKLF polypeptide. In someembodiments, the modified EKLF polypeptide comprises one, two, three,four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen,fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty,greater than twenty, greater than twenty-five, greater than thirty,greater than thirty-five, greater than forty, greater than forty-five,or greater than fifty amino acid modifications as compared to awild-type EKLF polypeptide. In some embodiments, the amino acidmodifications are substitutions, additions, deletions, or a combinationthereof.

In some embodiments, the genetically modified non-human animal expressesa modified EKLF polypeptide that comprises less than 100% identity towild-type EKLF. In particular embodiments, the transgenic animalexpresses a polypeptide greater than 80% identity, greater than 85%identity, greater than 90% identity, greater than 91% identity, greaterthan 92% identity, greater than 93% identity, greater than 94% identity,greater than 95% identity, greater than 96% identity, greater than 97%identity, greater than 98% identity, greater than 99% identity, but lessthan 100% identity to endogenous wild-type EKLF.

Particular embodiments contemplate that the function of the EKLFpolypeptide is tightly regulated by interactions with different cofactorpolypeptides and also by posttranslational modifications. EKLFassociates with transcriptional activators such as p300, CBP, and P/CAFthat have intrinsic histone acetyltransferase (HAT) activity, and EKLFitself is acetylated by p300 and CBP at two sites which results in itstranscriptional activation. EKLF stability is regulated by itsubiquitination status (Quadrini, K. J., and J. J. Bieker. 2006. FEBSLett. 580:2285-2293). Phosphorylation of threonine 41 is essential foroptimal transcriptional activity (Ouyang, L., X. Chen, and J. J. Bieker.1998. J. Biol. Chem. 273:23019-23025.) Further, sumoylation at lysine 74can regulate transcriptional repressor activity of EKLF (Siatecka et al.2007 Mol Cell Biol.: 27(24): 8547-8560), and nuclear import of EKLF(Shyu et al. 2014. Developmental Cell 28, 409-422).

In certain embodiments, the transgenic animal expresses a modified EKLFpolypeptide that has an altered, e.g. lacks, a post-translationalmodification compared to wild-type EKLF polypeptide. In particularembodiments, the transgenic animal expresses a modified EKLF polypeptidecomprising at least one amino acid modification, wherein the at leastone amino acid substitution prevents a post translational modificationof the EKLF polypeptide at the site of the post-translationalmodification. In some embodiments, post-translational modificationrefers to the modification of a polypeptide during or after proteinsynthesis. Post translational modifications include, but are not limitedto, phosphorylation, acetylation, methylation, glycosylation,lipidation, myristoylation, palmitoylation, farnesylation,geranylgeranylation, formylation, amidation, glypiation, lipoylation,acylation, butyrylation, malonylation, hydroxylation, S-nitrosylation,succinylation, sumoylation, ubiquitination, and Neddylation. In certainembodiments, the transgenic animal expresses a modified EKLF polypeptidewith an amino acid modification that prevents or inhibitsphosphorylation. In particular embodiments, the transgenic animalexpresses a modified EKLF polypeptide with an amino acid that preventsor inhibits sumoylation. In certain embodiments, the transgenic animalis an EKLF knock-in mouse that expresses a modified EKLF polypeptidethat has altered post-translational modification as compared towild-type EKLF polypeptide.

“Phosphorylation,” as used herein, refers to the addition of a phosphate(PO₄ ³⁻) group to an amino acid residue of a polypeptide. Reversibleprotein phosphorylation, principally on serine, threonine or tyrosineresidues, is one of the most important and well-studiedpost-translational modifications. Phosphorylation plays critical rolesin the regulation of many cellular processes including cell cycle,growth, apoptosis and signal transduction pathways. In certainembodiments, the transgenic animal expresses a modified EKLF polypeptidecomprising an amino acid modification that prevents phosphorylation ofthe modified EKLF polypeptide. In some embodiments, the modified EKLFpolypeptide comprises an amino acid modification that preventsphosphorylation on the modified amino acid residue.

“Sumoylation”, also referred to in the art as “SUMOylation,” is thecovalent linkage of a polypeptide to the SUMO protein (SmallUbiquitin-related MOdifier). SUMO proteins are a family of smallproteins that are covalently attached to and detached from otherproteins in cells to modify their function. Sumoylation is apost-translational modification involved in various cellular processes,such as nuclear-cytosolic transport, transcriptional regulation,apoptosis, protein stability, response to stress, and progressionthrough the cell cycle. In certain embodiments, the transgenic animalexpresses a modified EKLF polypeptide comprising an amino acidmodification that prevents summolaytion of the modified EKLF. In someembodiments, the modified EKLF polypeptide comprises an amino acidmodification that prevents sumoylation on the modified amino acidresidue.

Particular embodiments contemplate that EKLF polypeptide ispost-translationally modified by sumoylation at a single site, and thatthe E3 ligase PIAS1 plays a critical role in this process. Certainembodiments contemplate that the EKLF polypeptide is sumolyated atlysine at position 74 in mice, at lysine at position 54 in humans, or ata corresponding sumoylation site. Particular embodiments contemplatethat the human EKLF polypeptide is sumoylated at lysine at position 54.In certain embodiments, a sumoylation site that corresponds to lysine atposition 74 of the mouse EKLF polypetide is lysine at position 54 of thehuman EKLF polypeptide. Some embodiments contemplate that modificationto lysine 74 in mouse EKLF polypeptide, to lysine 54 in human EKLFpolypeptide, or to a corresponding sumoylation site in other EKLFpolypeptides, prevents sumoylation of the EKLF polypeptide. Inparticular embodiments, the genetically modified animal expresses amodified EKLF polypeptide that comprises a modification of lysine 74, ora corresponding sumoylation site, that prevents sumoylation of themodified EKLF polypeptide. In particular embodiments, the modificationis a substitution. In certain embodiments, the modification is a lysineto arginine substitution at position 74 in mouse EKLF polypeptide.

Particular embodiments contemplate that phosphorylation of serine atposition 68 in mice, or a corresponding phosphorylation site, by PKCtheta triggers the summoylation of the EKLF polypeptide. Someembodiments contemplate that an amino acid modification that preventsthe phosphorylation of EKLF at serine 68 prevents or reduces thelikelihood of EKLF sumoylation at the lysine at position 74. In certainembodiments, the genetically modified animal expresses a modified EKLFpolypeptide that comprises an amino acid modification that preventsphosphorylation at serine 68 and reduces or prevents sumoylation of themodified EKLF polypeptide. In certain embodiments, the geneticallymodified animal expresses a modified EKLF polypeptide comprising anamino acid modification at position 68 that prevents phosphorylation atposition 68 and reduces or prevents sumoylation of the modified EKLFpolypeptide. In particular embodiments, the modification is asubstitution. In certain embodiments, the modification is a serine toalanine substitution at position 68.

Certain embodiments contemplate that the human EKLF polypeptidecomprises one or more phosphorylation sites. In particular embodiments,phosphorylation at a phosphorylation site of the human EKLF polypeptidetriggers the sumoylation of the human EKLF polypeptide. Some embodimentscontemplate that an amino acid modification that prevents thephosphorylation of human EKLF polypeptide prevents or reduces thelikelihood of EKLF sumoylation at the lysine at position 54. In certainembodiments, a modified human EKLF comprises an amino acid modificationat a phosphorylation site that prevents phosphorylation and reduces orprevents sumoylation of the modified human EKLF polypeptide.

In some embodiments, the genetically modified non-human animal expressesa modified EKLF polypeptide that comprises a modification of at leastone amino acid, wherein the modification of the at least one amino acidprevents or reduces sumoylation of the EKLF polypeptide. In someembodiments, the genetically modified non-human animal expresses amodified EKLF polypeptide that comprises a modification of at least oneamino acid, wherein the modification of the at least one amino acidprevents sumoylation of the EKLF polypeptide. In some embodiments, themodification of the at least one amino acid reduces the amount ofmodified EKLF polypeptides that are sumoylated as compared to wild-typeEKLF polypeptide. In some embodiments, the modification of the at leastone amino acid reduces the amount of modified EKLF polypeptides that aresumoylated by about 5%, about 10%, about 15%, about 20%, about 25%,about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%,about 95%, or about 100% (including all integers and ranges in between)compared to the wild-type EKLF polypeptide. In some embodiments, themodification of the at least one amino acid reduces the probability thata modified EKLF polypeptide will be sumoylated. In some embodiments, themodification of the at least one amino acid reduces the probability thata modified EKLF polypeptide will be sumoylated by about 5%, about 10%,about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%,about 80%, about 85%, about 90%, about 95%, or about 100% (including allintegers and ranges in between).

In some embodiments, the genetically modified non-human animal expressesa modified EKLF polypeptide that comprises a modification of at leastone amino acid, wherein the modification of at least one amino acidprevents or reduces phosphorylation of the EKLF polypeptide. In someembodiments, the genetically modified non-human animal expresses amodified EKLF polypeptide that comprises a modification of at least oneamino acid, wherein the modification of at least one amino acid preventsphosphorylation of the EKLF polypeptide. In some embodiments, themodification of the at least one amino acid reduces the amount ofmodified EKLF polypeptides that are phosphorylated compared to wild-typeEKLF polypeptide. In some embodiments, the modification of the at leastone amino acid reduces the amount of modified EKLF polypeptides that arephosphorylated by about 5%, about 10%, about 15%, about 20%, about 25%,about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%,about 95%, or about 100% (including all integers and ranges in between)compared to the wild-type EKLF polypeptide. In some embodiments, themodification of the at least one amino acid reduces the probability thata modified EKLF polypeptide will be sumoylated. In some embodiments, themodification of the at least one amino acid reduces the probability thata modified EKLF polypeptide will be sumoylated by about 5%, about 10%,about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%,about 80%, about 85%, about 90%, about 95%, or about 100% (including allintegers and ranges in between).

In some embodiments, the genetically modified non-human animal expressesa modified EKLF polypeptide that comprises a modification of an aminoacid, wherein the modification of the amino acid prevents phosphoryationof the modified EKLF polypeptide at serine 68, or a correspondingphosphorylation site. In some embodiments, the genetically modifiednon-human animal expresses a modified EKLF polypeptide that comprises amodification of serine 68, or a corresponding phosphorylation site,wherein the modification prevents phosphorylation of sumoylation of theEKLF polypeptide. In certain embodiments, the modification is a serineto alanine substitution at position 68, or a correspondingphosphorylation site. In some embodiments, the modification thatprevents phosphorylation of serine 68, or a correspondingphosphorylation site, reduces the amount of modified EKLF polypeptidesthat are sumoylated. In some embodiments, the modification of the atleast one amino that prevents phosphorylation of serine 68, or acorresponding phosphorylation site, reduces the amount of modified EKLFpolypeptides that are sumoylated by about 5%, about 10%, about 15%,about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%,about 85%, about 90%, about 95%, or about 100% (including all integersand ranges in between) compared to wild-type EKLF polypeptide. In someembodiments, the modification that prevents phosphosphorylation of theamino acid at position 68, or a corresponding or differentphosphorylation site, reduces the probability that a modified EKLFpolypeptide will be sumoylated by about 5%, about 6%, about 7%, about8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%,about 15%, about 16%, about 17%, about 18% , about 19%, about 20%, about25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%,about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about90%, about 95%, or about 100% (including all integers and ranges inbetween) compared to wild-type EKLF polypeptide.

Certain embodiments contemplate that a modified EKLF polypeptideexpressed by a genetically modified animal may have altered propertiesor activities, e.g. stability, subcellular localization, ortranscriptional activity, as compared to a wild-type EKLF polypeptidedepending on the cell-type or tissue-type where the modified EKLFpolypeptide is expressed. Thus, in a given cell-type or tissue-type ofthe genetically modified animal, the property of the modified EKLFpolypeptide may be similar to or different from the property of thewild-type EKLF polypeptide in the equivalent cell or tissue. Therefore,in some embodiments, the genetically modified animal comprises acell-type or tissue-type where the property or activity of the modifiedEKLF polypeptide is different from the wild-type EKLF polypeptide andalso comprises a cell-type or tissue-type where the same property oractivity of the modified EKLF polypeptide is similar to the wild-typeEKLF polypeptide. In particular embodiments, a property or activity ofthe modified EKLF polypeptide is different from the wild-type EKLFpolypeptide in all of the cell-types and tissue-types of the geneticallymodified animal where EKLF is expressed.

Some embodiments contemplate that the modification of the EKLFpolypeptide does not alter the expression of the modified EKLFpolypeptide compared to the endogenous, wild-type EKLF polypeptide. Someembodiments contemplate that in a given cell or tissue of thegenetically modified animal, the levels of mRNA encoding modified EKLFpolypeptide will be similar to the levels of mRNA encoding wild-typeEKLF polypeptide in an equivalent cell or tissue type of a controlanimal, e.g. a littermate of the same gender. Particular embodimentscontemplate that in a given cell or tissue of the genetically modifiedanimal, the levels of the modified EKLF polypeptide will be similar tothe levels of mRNA encoding wild-type EKLF polypeptide in an equivalentcell or tissue type of a non-genetically modified animal of the samespecies.

In some embodiments, the genetically modified animal expresses amodified EKLF polypeptide, wherein the modification alters the stabilityof the modified EKLF compared to an endogenous, wild-type EKLFpolypeptide. In some embodiments, the modification of the EKLFpolypeptide increases the half-life of the modified EKLF by about 5%,about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%,about 75%, about 80%, about 85%, about 90%, about 95%, about 100%, about110%, about 120%, about 130%, about 140%, about 150%, about 200%, or byabout 2-fold, about 3-fold, about 4-fold, about 5-fold, about 6-fold,about 7-fold, about 8-fold, about 9-fold, about 10-fold, about 20-fold,about 30-fold, about 40-fold, about 50-fold, about 60-fold, about70-fold, about 80-fold, about 90-fold, about 100-fold, or by greaterthan 10-fold (including all integers and ranges in between), compared tothe endogenous, wild-type EKLF polypeptide. In some embodiments, themodification of the EKLF polypeptide reduces the half-life of themodified EKLF by about 5%, about 6%, about 7%, about 8%, about 9%, about10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%,about 17%, about 18% , about 19%, about 20%, about 25%, about 30%, about35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%,about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, orabout 100% (including all integers and ranges in between) compared tothe wild-type EKLF polypeptide.

In some embodiments, the genetically modified animal expresses amodified EKLF polypeptide, wherein the modification alters thesubcellular localization of the modified EKLF compared to an endogenous,wild-type EKLF polypeptide. In some embodiments, the modification of theEKLF polypeptide increases the cytosolic localization of the modifiedEKLF by about 5%, about 10%, about 15%, about 20%, about 25%, about 30%,about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%,about 100%, about 110%, about 120%, about 130%, about 140%, about 150%,about 200%, or by about 2-fold, about 3-fold, about 4-fold, about5-fold, about 6-fold, about 7-fold, about 8-fold, about 9-fold, about10-fold, about 20-fold, about 30-fold, about 40-fold, about 50-fold,about 60-fold, about 70-fold, about 80-fold, about 90-fold, about100-fold, or by greater than 100-fold (including all integers and rangesin between), compared to the endogenous, wild-type EKLF polypeptide. Insome embodiments, the modification of the EKLF polypeptide reduces thenuclear localization of the modified EKLF by about 5%, about 6%, about7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%,about 14%, about 15%, about 16%, about 17%, about 18% , about 19%, about20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%,about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about85%, about 90%, about 95%, or about 100% (including all integers andranges in between) as compared to the wild-type EKLF polypeptide. Inparticular embodiments, subcellular localization of the modified EKLFpolypeptide is altered in the progenitors and precursor cells of theerythroid lineage. In some embodiments, subcellular localization isaltered in cells undergoing erythroid maturation during the transitionfrom pro-erythroblast (Pro-E) to basophilic erythroblast (Baso-E). Incertain embodiments, subcellular localization is altered during orfollowing DMSO-induced murine erythroleukemia (MEL) celldifferentiation.

In some embodiments, the genetically modified animal expresses amodified EKLF polypeptide, wherein the modification increases thetranscriptional activation activity, i.e. the promotion of transcriptionof a target gene or genes, of the modified EKLF compared to anendogenous, wild-type EKLF polypeptide. In some embodiments, themodified EKLF polypeptide increases the transcription of at least onegene by about 5%, about 10%, about 15%, about 20%, about 25%, about 30%,about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%,about 100%, about 110%, about 120%, about 130%, about 140%, about 150%,about 200%, or by about 2-fold, about 3-fold, about 4-fold, about5-fold, about 6-fold, about 7-fold, about 8-fold, about 9-fold, about10-fold, about 20-fold, about 30-fold, about 40-fold, about 50-fold,about 60-fold, about 70-fold, about 80-fold, about 90-fold, about100-fold, or by greater than 100-fold (including all integers and rangesin between) as compared to the transcription of the gene promoted by thewild-type EKLF. In some embodiments, the modified EKLF polypeptidepromotes an increase in transcription of one, two, three, four, five,six, seven, eight, nine, ten, greater than ten, greater than fifteen,greater than twenty, greater than twenty-five, greater than thirty,greater than forty, greater than fifty, greater than sixty, greater thanseventy, greater than eighty, greater then ninety, greater than 100,greater than 200, greater than 300, greater than 400, greater then 500,or greater than 1,000 genes that are not transcriptionally promoted bythe wild-type EKLF polypeptide.

In some embodiments, the genetically modified animal expresses amodified EKLF polypeptide, wherein the modification increases thetranscriptional repression activity, i.e. repression of transcription ofa target gene or genes, of the modified EKLF compared to an endogenous,wild-type EKLF polypeptide. In some embodiments, the modified EKLFpolypeptide represses the transcription of at least one gene by about5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%,about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 100%,about 110%, about 120%, about 130%, about 140%, about 150%, about 200%,or by about 2-fold, about 3-fold, about 4-fold, about 5-fold, about6-fold, about 7-fold, about 8-fold, about 9-fold, about 10-fold, about20-fold, about 30-fold, about 40-fold, about 50-fold, about 60-fold,about 70-fold, about 80-fold, about 90-fold, about 100-fold, or bygreater than 100-fold (including all integers and ranges in between) ascompared to the transcription of the gene promoted by the wild-typeEKLF. In some embodiments, the modified EKLF polypeptide represses thetranscription of one, two, three, four, five, six, seven, eight, nine,ten, greater than ten, greater than fifteen, greater than twenty,greater than twenty-five, greater than thirty, greater than forty,greater than fifty, greater than sixty, greater than seventy, greaterthan eighty, greater then ninety, greater than 100, greater than 200,greater than 300, greater than 400, greater then 500, or greater than1,000 genes that are not repressed by the wild-type EKLF polypeptide.

In some embodiments, the genetically modified animal expresses amodified EKLF polypeptide, wherein the modification decreases thetranscriptional activation activity, i.e. the promotion of transcriptionof a target gene or genes, of the modified EKLF compared to anendogenous, wild-type EKLF polypeptide. In some embodiments, themodified EKLF polypeptide decreases the transcription of at least onegene by about 5%, about 10%, about 15%, about 20%, about 25%, about 30%,about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%,or about 100% (including all integers and ranges in between) as comparedto the transcription of the gene promoted by the wild-type EKLF. In someembodiments, the modified EKLF polypeptide promotes an increase intranscription of one, two, three, four, five, six, seven, eight, nine,ten, greater than ten, greater than fifteen, greater than twenty,greater than twenty-five, greater than thirty, greater than forty,greater than fifty, greater than sixty, greater than seventy, greaterthan eighty, greater then ninety, greater than 100, greater than 200,greater than 300, greater than 400, greater then 500, or greater than1,000 less genes that are transcriptionally promoted by the wild-typeEKLF polypeptide.

In some embodiments, the genetically modified animal expresses amodified EKLF polypeptide, wherein the modification decreases thetranscriptional repression activity, i.e. repression of transcription ofa target gene or genes, of the modified EKLF compared to an endogenous,wild-type EKLF polypeptide. In some embodiments, the modified EKLFpolypeptide reduces the repression of the transcription of at least onegene by about 5%, about 10%, about 15%, about 20%, about 25%, about 30%,about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%,or about 100% (including all integers and ranges in between) as comparedto the transcription of the gene repressed by the wild-type EKLFpolypeptide. In some embodiments, the modified EKLF polypeptiderepresses the transcription of one, two, three, four, five, six, seven,eight, nine, ten, greater than ten, greater than fifteen, greater thantwenty, greater than twenty-five, greater than thirty, greater thanforty, greater than fifty, greater than sixty, greater than seventy,greater than eighty, greater then ninety, greater than 100, greater than200, greater than 300, greater than 400, greater then 500, or greaterthan 1,000 less genes that are repressed by the wild-type EKLFpolypeptide.

Certain embodiments are directed to genetically modified animals thatexpress modified EKLF polypeptide with enhanced lifespan, health span,and/or cancer resistance compared to control animals that expresswild-type EKLF polypeptide. Particular embodiments contemplate a modelwhereby the enhancement of lifespan, health span, and/or cancerresistance are conferred by the modified EKLF polypeptide through amechanism that is distinct from existing animal models of longevity andcancer resistance. This model is based on observations that phenotypesobserved in the animals expressing modified EKLF are distinct from thephenotypes observed in previously described models of longevity, e.g.calorie restricted animals, animal administered metformin, IGF1 receptorknockout animals, transgenic PTEN animals, Heterozygous Myc knockoutanimals, animals administered rapamycin, S6K1 knockout animals, Fat10knockout animals, Sirtl mutant animals, and transgenic Cisd2 animals.Particular embodiments contemplate that expression of modified EKLFpolypeptides extends lifespan and health span without altering one ormore of metabolism, fertility, autophagy homeostasis, genomic stability,or mitochondrial function.

In some embodiments, genetically modified animals that express modifiedEKLF polypeptide have increased lifespan compared to control animalsthat express wild-type EKLF polypeptide. In particular embodiments, theincreased lifespan is manifested as an increase in the mean lifespancompared to control animals. In certain embodiments, the increasedlifespan is manifested as an increase in the maximum age the animal canreach compared to control animals. In some embodiments, the increasedlifespan is manifested as an increase in the maximum lifespan, i.e. themean lifespan of the longest-lived 10% of a population. In particularembodiments, genetically modified animals that express modified EKLFpolypeptide have increased lifespan of about 5%, about 6%, about 7%,about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%,about 21%, about 22%, about 23%, about 24%, about 25%, about 26%, about27%, about 28%, about 29%, about 30%, about 35%, about 45%, about 50%,about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about85%, about 90%, about 95%, or about 100% (including all integers andranges in between) as compared to control animals that express wild-typeEKLF.

In some embodiments, genetically modified animals that express modifiedEKLF polypeptide have increased health span compared to control animalsthat express wild-type EKLF polypeptide. Health span refers to thelength of time where the organism is in optimal health, e.g. free fromage-related diseases. In particular embodiments, genetically modifiedanimals that express modified EKLF polypeptide have increased healthspan of about 5%, about 6%, about 7%, about 8%, about 9%, about 10%,about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23%,about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, about30%, about 35%, about 45%, about 50%, about 55%, about 60%, about 65%,about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about100% (including all integers and ranges in between), or greater than100%, as compared to control animals that express wild-type EKLF.Increased health span may be measured with respect to one or morephysical attributes associated with increased health, including but notlimited to any of those described herein.

In certain embodiments, genetically modified animals that expressmodified EKLF polypeptide have delayed onset and/or slower progressionof aging-related symptoms. In particular embodiments, aged geneticallymodified animals show less severity of at least one aging-relatedsymptoms, e.g. gray hairs, muscle weakness, motor coordination,osteoporosis, loss of balance, cancer incidence, susceptibility tochemical stress, susceptibility to infection, or susceptibility toinflammation, than aged-matched controls. In particular embodiments,genetically modified animals expressing modified EKLF polypeptideexperience a delayed onset of aging relating symptoms, as compared to ascompared to age-matched control animals. In certain embodiments,genetically modified animals expressing modified EKLF polypeptideexperience a slower progression of aging relating symptoms, as comparedto as compared to age-matched control animals.

In certain embodiments, genetically modified animals that expressmodified EKLF polypeptide have a delayed onset and/or a slowerprogression of age-related changes, e.g., in muscle strength and motorcoordination. Particular embodiments contemplate that normal aging isaccompanied by progressive weakness and loss of motor coordination. Incertain embodiments, young genetically modified animals that expressmodified EKLF polypeptide have similar muscle strength and motorcoordination as young control animals that express wild-type EKLFpolypeptide; and aged genetically modified animals that express modifiedEKLF polypeptide greater muscle strength and motor coordination ascompared to young control animals that express wild-type EKLFpolypeptide. In particular embodiments, genetically modified animalsthat express modified EKLF retain about 50%, about 51%, about 52%, about53%, about 54%, about 55%, about 56%, about 57%, about 58%, about 59%,about 60%, about 61%, about 62%, about 63%, about 64%, about 65%, about66%, about 67%, about 68%, about 69%, about 70%, about 71%, about 72%,about 73%, about 74%, about 75%, about 76%, about 77%, about 78%, about79%, about 80%, about greater than 80%, about greater than 85%, aboutgreater than 90%, about greater than 95%, about greater than 99%, oftheir muscle strength and motor coordination throughout the progressionof their lifespan. Those of skill in the art will recognize methodssuitable for measuring and evaluating muscle strength and motorcoordination, including but not limited to the rotarod test and the gripstrength test.

In certain embodiments, aged genetically modified animals that expressmodified EKLF have increased muscle strength of about 5%, about 10%,about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%,about 80%, about 85%, about 90%, about 95%, about 100%, about 110%,about 120%, about 130%, about 140%, about 150%, about 200%, or by about2-fold, about 3-fold, about 4-fold, about 5-fold, about 6-fold, about7-fold, about 8-fold, about 9-fold, about 10-fold (including all rangesand integers in between), or about greater than 10-fold compared toage-matched control animals. In particular embodiments, aged geneticallymodified animals that express modified EKLF have increased motorcoordination as compared to age-matched control animals of about 5%,about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%,about 75%, about 80%, about 85%, about 90%, about 95%, about 100%, about110%, about 120%, about 130%, about 140%, about 150%, about 200%, or byabout 2-fold, about 3-fold, about 4-fold, about 5-fold, about 6-fold,about 7-fold, about 8-fold, about 9-fold, about 10-fold (including allranges and integers in between), or about greater than 10-fold.

Particular embodiments contemplate that osteoporosis can develop as asymptom of normal aging, and that normal aging can be accompanied by areduction in bone volume and trabecular number, and an increase intrabecular spacing. In certain embodiments, genetically modified animalsthat express modified EKLF do not develop osteoporosis during theprogression of their lifespan. In some embodiments, genetically modifiedanimals that express modified EKLF do not experience a reduction in bonevolume and/or trabecular number throughout the progression of theirlifespan. In some embodiments, genetically modified animals that expressmodified EKLF do not experience an increase in trabecular spacingthroughout the progression of their lifespan. In certain embodiments,genetically modified animals that express modified EKLF have slower rateof development of osteoporosis during the progression of their lifespanas compared to age-matched control animal that express wild-type EKLF.In some embodiments, genetically modified animals that express modifiedEKLF have a slower progression of the reduction in bone volume and/ortrabecular number throughout the progression of their lifespan ascompared to age-matched control animals. In some embodiments,genetically modified animals that express modified EKLF have a slowerprogression of the increase in trabecular spacing throughout theprogression of their lifespan.

In certain embodiments, aged genetically modified animals that expressmodified EKLF have increased bone volume of about 5%, about 10%, about15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%,about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about80%, about 85%, about 90%, about 95%, about 100%, about 110%, about120%, about 130%, about 140%, about 150%, about 200%, or by about2-fold, about 3-fold, about 4-fold, about 5-fold, about 6-fold, about7-fold, about 8-fold, about 9-fold, about 10-fold (including all rangesand integers in between), or about greater than 10-fold compared toage-matched control animals. In certain embodiments, aged geneticallymodified animals that express modified EKLF have increased trabecularnumber of about 5%, about 10%, about 15%, about 20%, about 25%, about30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%,about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about95%, about 100%, about 110%, about 120%, about 130%, about 140%, about150%, about 200%, or by about 2-fold, about 3-fold, about 4-fold, about5-fold, about 6-fold, about 7-fold, about 8-fold, about 9-fold, about10-fold (including all ranges and integers in between), or about greaterthan 10-fold compared to age-matched control animals. In certainembodiments, aged genetically modified animals that express modifiedEKLF have decreased trabecular spacing by about 5%, about 6%, about 7%,about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about14%, about 15%, about 16%, about 17%, about 18% , about 19%, about 20%,about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%,about 90%, about 95%, or about 100% (including all integers and rangesin between) as compared to age-matched control animals.

Particular embodiments contemplate that genetically modified animalsthat express a modified EKLF polypeptide have a lower probability ofdeveloping a cellular proliferative disorder, i.e. cancer, throughouttheir lifespan as compared to control animals that express wild-typeEKLF. In some embodiments, a genetically modified animal expressing amodified EKLF polypeptide has a reduced probability of developing cancerthroughout its lifetime of about 5%, about 6%, about 7%, about 8%, about9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%,about 16%, about 17%, about 18% , about 19%, about 20%, about 25%, about30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%,about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about95%, or about 100% (including all integers and ranges in between)compared to a control animal. In particular embodiments, the geneticallymodified animal is less likely to develop a cellular proliferativedisorder selected from liver cancer, colon cancer, breast cancer,prostate cancer, hepatocellular carcinoma, melanoma, lung cancer,glioblastoma, brain tumor, hematopoietic malignancies, retinoblastoma,renal cell carcinoma, head and neck cancer, cervical cancer, pancreaticcancer, esophageal cancer, or squama cell carcinoma compared to an agedmatched control. In some embodiments, the genetically modified animalthat expresses modified EKLF has a lower probability of developingmelanoma over its lifespan than a control animal.

Certain embodiments contemplate that the expression of modified EKLFpolypeptide by a genetically modified animal suppresses the growth of atumor or cancer, or suppresses the ability of a tumor, cancer cell orprecancerous cell to undergo metastasis. Some embodiments contemplatethat the expression of modified EKLF polypeptide by a geneticallymodified animal suppresses the ability of a tumor, cancer cell orprecancerous cell to undergo metastasis, but does not alter the rate oftumor growth. Particular embodiments contemplate that the intravenousinjection of precancerous or cancer cells, e.g. B16F10 melanoma cells,into a genetically modified animal that expresses modified EKLFpolypeptide will result in cancer metastasis and tumor formation thatare significantly reduced compared to control animals intravenouslyinjected with precancerous or cancer cell. In certain embodiments, acancer cell or precancerous cell has a reduced likelihood of forming atumor in a genetically modified animal that expresses modified EKLF ascompared to a cancer cell or precancerous cell in a control animal. Inparticular embodiments, a cancer cell or precancerous cell has reducedincidence of metastasis in a genetically modified animal that expressesmodified EKLF as compared to a cancer cell or precancerous cell in acontrol animal. In some embodiments, the cancer cell or precancerouscell does not comprise a modification at the EKLF locus and does notexpress modified EKLF.

In some embodiments, a precancerous or cancer cell is in a geneticallymodified animal that expresses a modified EKLF polypeptide, and growthor metastasis of the cell is reduced by about 5%, about 6%, about 7%,about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about14%, about 15%, about 16%, about 17%, about 18% , about 19%, about 20%,about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%,about 90%, about 95%, or about 100% (including all integers and rangesin between) compared to an equivalent cell in a control animal. In someembodiments, the precancerous or cancer cell is intravenously injectedinto the genetically modified animal. In some embodiments, the cell is aB16F10 melanoma cell.

In some embodiments, a precancerous or cancer cell is in a geneticallymodified animal that expresses a modified EKLF polypeptide, and thenumber of tumors the cell can form is reduced by about 5%, about 6%,about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about13%, about 14%, about 15%, about 16%, about 17%, about 18% , about 19%,about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%,about 85%, about 90%, about 95%, or about 100% (including all integersand ranges in between) compared to an equivalent cell in a controlanimal. In some embodiments, the precancerous or cancer cell isintravenously injected into the genetically modified animal. In someembodiments, the cell is a B16F10 melanoma cell.

Particular embodiments are directed to an EKLF knock-in mouse thatexpresses a modified EKLF polypeptide, wherein the modified EKLFpolypeptide comprises at least one amino acid modification that preventssumoylation of the modified EKLF polypeptide, and wherein the EKLFknock-in mouse has enhance longevity, extended health span, and/orresistance to tumorigenesis and cancer metastasis. Certain embodimentsare directed to an EKLF knock-in mouse that expresses a modified EKLFpolypeptide, wherein the modified EKLF polypeptide comprises a lysine toarginine substitution at position 74, wherein the EKLF knock-in mousehas enhance longevity, extended health span, and/or resistance totumorigenesis and cancer metastasis.

Methods of Identifying Agents that Enhance Longevity and/or DecreaseTumorigenicityor Tumor Metastasis

The present invention includes methods for identifying active agentsthat confer increased longevity, extended life span, extended healthspan, decreased tumorigenesis, and/or decreased tumor metastasis to asubject, e.g., a mammal such as a human. Such methods of the inventionare based on the unexpected finding that modifications of EKLF havethese effects in mammals. As described herein, the term “tumorigenesis”refers to the initiation or onset of a tumor, i.e., the occurrence of atumor. The composition and methods described herein may also be used toachieve, or retain for a longer period of time, a specific phenotype orcharacteristic associated with youthfulness or increased longevity,including any of those described or demonstrated herein, such as reducedgraying of the hair, increased motor coordination, increased musclestrength, reduced muscle weakness, increased motor coordination, reducedosteoporosis, greater bone volume, greater bone density, greatertrabecular number, reduced trabecular spacing, reduced loss of balance,e.g., as compared to untreated subjects of the same age. Accordingly,the methods described below may be used to identify active agents thatconfer any of these phenotypes or characteristics to a treated subject.

In certain embodiments, a method of identifying an active agent capableof increasing longevity, life span or health span and/or inhibitingtumorigenesis or tumor metastasis of a subject comprises identifying anagent that alters one or more post-translational modifications of anEKLF polypeptide, e.g., a human EKLF protein. In particular embodiments,the post-translational modification is sumoylation or phosphorylation.Reversible post-translational modifications including sumoylation andphosphorylation play important roles in the nucleic import of certainproteins, including EKLF. It has been shown that murine EKLF issumoylated at Lys74, which is located within a consensus negativelycharged amino acid-dependent sumoylation motif. The correspondingsumoylation site of human EKLF is located at Lys54. Without wishing tobe bound to any particular theory, it is thought that sumoylation may ormay not reduce nuclear translocation of EKLF. In addition, it is thoughtthat sumoylation may alter the transcriptional activity, e.g., activatoror repressor activity, of EKLF on one or more EKLF target genes.

Small ubiquitin related modifier (SUMO) was discovered as a modifier ofmammalian proteins (Sarge, K. and Parke-Sarge, O-K., Methods in Mol.Biol. 2009; 590: 265-277 (2010)). As described therein, proteinsumoylation does not promote degradation of proteins but insteadregulates functional properties of target proteins, such as subcellularlocalization, protein partnering, and transactivation functions oftranscription factors. SUMO proteins are covalently attached to lysineresidues of proteins, which are generally found within the consensusmotif ΨKXE where ΨP is a hydrophobic amino acid and X is any residue.The covalent attachment of SUMO to other proteins involves a series ofenzymatic steps in vivo. First, the SUMO proteins undergo proteolyticprocessing near their C-terminal end to form the mature proteins, a stepwhich is performed by SUMO proteases (Ulp's). These proteases aredual-functional, as they are also responsible for cleaving SUMO groupsfrom substrate proteins by cleaving the isopeptide bonds by which theyare joined. The mature processed SUMO protein is covalently attached viaa thioester bond to the SAE2 (Uba2) subunit of the heterodimeric SUMO Elactivating enzyme in an ATP-dependent reaction). The SUMO moiety istransferred from the E1 to ubc9, the SUMO E2 enzyme, which then binds tothe ΨKXE consensus sequence in target proteins and forms an isopeptidebond between the c-amino group of the lysine within this sequence andthe carboxyl group of the C-terminal glycine of the SUMO polypeptide.SUMO E3 proteins have been identified that enhance the efficiency ofSUMO attachment by interacting with both ubc9 (the E2 enzyme) and thesubstrate, thereby acting as bridging factors. Vertebrate cells containthree SUMO paralogs. SUMO-2 and SUMO-3 are very similar to each other insequence, and have approximately 50% sequence identity with SUMO-1,which is the best characterized of the three vertebrate SUMO proteins.

The protein kinase C theta (PKCΘ)-mediated Ser68 phosphorylation site ofEKLF is close to Lys74, and it has been hypothesized that Ser68phosphorylation coupled sumoylation at Lys74 facilitates the nuclearimport of EKLF, and that Ser68 phosphorylation of EKLF might not onlydissociate EKLF from FOE, but it might also affect the sumoylation ofEKLF, playing a regulatory role in the nuclear import of EKLF duringerythroid maturation (Yang et al. (2006) EMBO J. 25, 5083-5093). Withoutwishing to be bound to any particular theory, it is believed that activeagents that inhibit phosphorylation of Ser68 or sumoylation of Lys74 mayor may not inhibit the translocation of EKLF to the nucleus, thusaffecting its ability to transcriptionally activate or repress targetgenes. In addition, it is thought that active agents that inhibitphosphorylation of Ser68 or sumoylation of Lys74 may alter thetranscriptional activity, e.g., activator or repressor activity, of EKLFon one or more EKLF target genes.

In one embodiment, a method of identifying an active agent comprises:contacting an EKLF polypeptide, e.g., a human EKLF protein, with acandidate agent; and measuring an amount of a post-translationalmodification present on the EKLF polypeptide, wherein the candidateagent is considered an active agent if the measured amount of thepost-translational modification on the EKLF polypeptide is significantlydifferent than (e.g., less than) a predetermined amount or significantlydifferent than (e.g., less than) the amount on a control EKLFpolypeptide that was not contacted with the candidate agent. Inparticular embodiments, the method further comprises measuring an amountof post-translational modification present on the EKLF polypeptide notcontacted with the candidate agent. In particular embodiments, thepre-determined amount is zero, or the pre-determined amount indicatesthat less than 10%, less than 20%, or less than 50% or the EKLFpolypeptide contains the post-translational modification.

In various embodiments, the EKLF polypeptide is contacted with thecandidate agent before and/or while performing an assay to detect thepresence of the post-translational modification, e.g., an in vitrophosphorylation or sumoylation assay. In particular embodiments, theassay comprises contacting an EKLF polypeptide with the enzyme(s) thatperforms the post-translational modification of the EKLF polypeptide,e.g., in the presence of a chemical group that is attached to the EKLFpolypeptide, such as a phosphate group or a SUMO protein, for a timesufficient and under conditions that allow the post-translationalmodification to occur, and then determining the amount of EKLFpolypeptide that comprises the post-translational modification or theamount of the post-translational modification present on the EKLFpolypeptide. The EKLF polypeptide may be contacted with various amountsof the candidate agent, e.g., to measure an IC50 for the candidateagent.

In particular embodiments wherein the post-translational modification issumoylation, the ELKL polypeptide is contacted with the candidate agenteither before or while performing an in vitro sumoylation assay. Suchassays are known in the art and kits for performing such assays areavailable, e.g., ENZO Sumoylation Kit (Farmingdale, N.Y., USA). Inparticular embodiments, the EKLF polypeptide is contacted with thecandidate agent in the presence of SUMO-1, -2, and/or -3 underconditions and for a time sufficient to allow sumoylation, and then SUMOspecific antibodies are used to detect sumoylated EKLF protein, e.g.,via SDS-PAGE or Western blotting.

In certain embodiments wherein the post-translational modification issumoylation, an EKLF polypeptide is in vitro translated in the presenceof a radioactive label (e.g., ³⁵S-Met) and then contacted with thecandidate agent before or while incubated in a reaction containing theSUMO E1 and E2 enzymes and SUMO-1 under conditions and for a timesufficient to allow sumoylation of the EKLF polypeptide, followed bySDS-PAGE and autoradiography to determine whether a sumoylated form ofthe EKLF polypeptide is present or not.

In certain embodiments wherein the post-translational modification isphosphorylation, EKLF polypeptide is in vitro translated in the presenceof a radioactive label (e.g., ³⁵S-Met) is contacted with the candidateagent before or while incubated with PKCΘ and phosphate group underconditions and for a time sufficient to allow phosphorylation of theEKLF polypeptide, and then analyzed by autoradiography or IB.Alternatively, phosphorylated protein may be isolated by SDS-PAGE andanalyzed by mass spectrometry. Related methods are described in Shyu,Y-C. et al., (2014) Developmental Cell 28: 409-422.

In another embodiment, a method of identifying an active agentcomprises: contacting a cell comprising an EKLF polypeptide with acandidate agent; and measuring an amount of a post-translationalmodification present on the EKLF polypeptide, wherein the candidateagent is considered an active agent if the measured amount of thepost-translational modification on the EKLF polypeptide is significantlydifferent than (e.g., less than) a predetermined amount or significantlydifferent than (e.g. less than) the amount on a control EKLF polypeptidethat was not contacted with the candidate agent. In particularembodiments, the method further comprises measuring an amount ofpost-translational modification present on the EKLF polypeptide notcontacted with the candidate agent.

In various embodiments, the cell comprising the EKLF polypeptidecomprises an exogenously introduced EKLF polypeptide, e.g., a human EKLFprotein. In certain embodiments, the cell comprises an expression vectorthat expresses the exogenous EKLF protein. The expression vector may bestably integrated into the cell's genome or transiently present in thecell. In certain embodiments, EKLF protein is introduced into the cellby microinjection or the use of a lipid delivery vehicle. In particularembodiments, the assay comprises contacting the cell comprising the EKLFpolypeptide with an agent that promotes or stimulates thepost-translational modification of the EKLF polypeptide, e.g. PMA, EPO,PKC theta activators, or SUMO polypeptides, for a time sufficient andunder conditions that allow the post-translational modification tooccur, and then determining the amount of EKLF polypeptide thatcomprises the post-translational modification or the amount of thepost-translational modification present on the EKLF polypeptide. Thecell comprising the EKLF polypeptide may be contacted with variousamounts of the candidate agent, e.g., to measure an IC50 for thecandidate agent.

In particular embodiments wherein the post-translational modification issumoylation, the polypeptide or cell is contacted with the active agentunder conditions and for a time sufficient for sumoylation of the EKLFpolypeptide to occur, and then a sumoylation assay is performed. Suchassays are known in the art, e.g. in vivo sumoylation assays. Forexample, the cell may then be lysed and sumoylated proteins detected byimmunoprecipitation (IP) analysis using a primary antibody that binds toEKLF, species-matched non-specific IgG, and antibodies against SUMO-1,SUMO-2, or SUMO-3 (Invitrogen). Other methods that may be employedinclude but are not limited to in vivo IP-Western blotting, IP-MS, DNAtransfection, DNA transfection-IP-Western blotting. Illustrative methodsare also described in Sarge, K. and Parke-Sarge, O-K., Methods in Mol.Biol. 2009; 590: 265-277 (2010)).

In certain embodiments wherein the post-translational modification isphosphorylation, a polypeptide or cell is contacted with the activeagent under conditions and for a time sufficient for phosphorylation ofthe EKLF polypeptide to occur, and then phosphorylated EKLF protein isdetected using any of a variety of assays known and available in the arte.g., in vitro phospholylation. For example, the cell may be lysed andphosphorylated EKLF protein detected by immunoprecipitation analysisusing a primary antibody that binds specifically to the phosphorylatedform of EKLF (phosphorylated at Ser68), and a detectable secondaryantibody. Other illustrative methods that may be employed include invivo IP-Western blotting, IP-MS, DNA transfection, DNAtransfection-IP-Western blotting, and Western blotting.

In various embodiments that include measuring the amount of apost-translational modification on an EKLF polypeptide, thepost-translational modification is sumoylation or phosphorylation. Inparticular embodiments, it is sumoylation of murine EKLF Lys74 or humanEKLF Lys54 or phosphorylation of murine EKLF Ser68. In particularembodiments, it is phosphorylation by P-PKCθ(5676). Methods ofdetermining the presence of or an amount of sumoylation orphosphorylation of a polypeptide are known and available in the art. Forexample, illustrative methods that may be employed are described in Yanget al. (2006) EMBO J. 25, 5083-5093; Shyu et al. (2006) Cell Res. 16,347-355; Siatecka et al. (2007) Mol Cell Biol. 27(24):8547-60; and Shyu,et al. (2014) Developmental Cell, 28, 409-422.

In certain embodiments that include measuring the amount of apost-translational modification on an EKLF polypeptide, the candidateagent is determined to be an active agent if the amount of thepost-translational modification present on the EKLF polypeptidecontacted with the candidate agent is less than 90%, less than 80%, lessthan 70%, less than 60%, less than 50%, less than 40%, less than 30%,less than 20%, less than 10%, or 0% as compared to the amount on theEKLF polypeptide not contacted with the candidate agent. In certainembodiments, the candidate agent is determined to be an active agent ifthe amount of the post-translational modification present on the EKLFpolypeptide is less than or equal to a pre-determined cut-off value,which may be determined using agents know to inhibit phosphorylation orsumoylation. In particular embodiments, the pre-determined cut-off valueis zero.

In certain embodiments, a method of identifying an active agent capableof increasing longevity, life span or health span and/or inhibitingtumorigenesis or tumor metastasis of a subject comprises identifying anagent that alters one or more activities of an EKLF polypeptide, e.g., ahuman EKLF protein. In particular embodiments, the activity is nucleartranslocation, transcriptional activation or transcriptional repression.Data suggests that in the progenitors and precursor cells of theerythroid lineage, EKLF is located mainly in the cytoplasm, and it istranslocated from the cytoplasm to the nucleus during erythroidmaturation (Yang et al. (2006) EMBO J. 25, 5083-5093). Without wishingto be bound to any particular theory, it is believed that nuclear importof EKLF is necessary for effective activation of adult □ globin genetranscription. An EKLF-interacting factor, Foe of EKLF (FOE) interactswith and sequesters EKLF in the cytoplasm, thus determining thefunctional restriction of EKLF in erythroid progenitor cells, which inturn regulates the activation or repression by EKLF of a set oferythroid genes during CFU-E/Pro-E to Baso-E transition of the erythroidlineage.

In another embodiment, a method of identifying an active agentcomprises: contacting a cell comprising an EKLF polypeptide, e.g., ahuman EKLF protein, with a candidate agent; and measuring an amount ofan activity of the EKLF polypeptide, wherein the candidate agent isconsidered an active agent if the measured amount of the activity theEKLF polypeptide is significantly different than (e.g., more than orless than) a predetermined amount or significantly different than (e.g.,more than or less than) the amount of a control EKLF polypeptide thatwas not contacted with the candidate agent. In particular embodiments,the method further comprises measuring an amount of an activity of theEKLF polypeptide not contacted with the candidate agent. In certainembodiments, the methods are practiced using an EKLF polypeptide insteadof cells comprising an EKLF polypeptide, e.g., when the activity istransactivator activity or repressor activity.

Methods of determining nuclear localization of a polypeptide are knownand available in the art. For example, methods that may be employed aredescribed in Yang et al. (2006) EMBO J. 25, 5083-5093, such asdetermining the subcellular (e.g., cytoplasmic or nuclear) localizationof the EKLF polypeptide by immunofluorescence. Accordingly, in onemethod, a cell comprising an EKLF polypeptide is contacted with acandidate agent under conditions and for a time sufficient for nuclearlocalization, and then the subcellular localization of the EKLFpolypeptide is determined by immunofluorescence using an antibodyspecific for EKLF. In particular embodiments, the assay is performedusing megakaryocyte/erythroid precursor cells, or mature erythrocytes.In certain embodiments, the assay is performed using cells at adifferentiation stage before, during or following the CFU-E/Pro-E toBaso-E transition. In particular embodiments, the cells are sortedCFU-E/ProE, Baso-E, PolyCh-E, or OrthoCh-E cells. Related methods aredescribed in Shyu, Y-C. et al., (2014) Developmental Cell 28: 409-422.

Methods of determining the transcription activity (e.g., transactivationor repression) of an EKLF polypeptide are also known and available inthe art and include, e.g., assays to determine binding of EKLF to atarget polynucleotide sequence, or transactivator or repressor activity,such as band-shift assays to measure binding of the EKLF to a targetpromoter or enhancer sequence, in vitro transcription assays using EKLFpolypeptide and reporter constructs, and quantitative polymerase chainreaction (PCR) to determine the mRNA expression levels of genesactivated or repressed by EKLF, e.g., in cells. Examples of genes thatare regulated by EKLF include but are not limited to: genes that areupregulated by EKLF such as alpha globin, beta globin, Epb4.9, Tspo2,and Fn3k; and genes that are downregulated by EKLF such as Hecw1, Nrip3,and Jak3. Additional genes that are regulated by EKLF are known in theart and include, e.g., those described in Bieker et al. 1995, Mol. Cell.Biol. 15:852-860; Chen and Bieker, 2004, Mol. Cell. Biol.24:10416-10424; Chen and Bieker, 2001, Mol. Cell. Biol. 21:3118-3125;Miller and Bieker, 1993, Mol. Cell. Biol. 13:2776-2786. In particularembodiment, the mRNA of the Col1a and/or Mpv171 genes are determined. Asshown in the accompanying Examples, the mRNA levels of both these genewas reduced in EKLF mutant mice having increase longevity and reducedtumor incidence and metastasis. In certain embodiments, a cellcomprising an EKLF polypeptide is contacted with a candidate agent, andthe expression levels of any of these genes is determined, e.g., byRT-PCR to determine if their expression varies as compared to theirexpression levels, e.g., as compared to a control value or in a cell notcontacted with the candidate agent.

In particular embodiments, an EKLF polypeptide is contacted with acandidate agent before or during incubation with a labeledpolynucleotide comprising an EKLF binding site, e.g., a promoter orenhancer element, under conditions and for a time sufficient to allowbinding of the EKLF to the polynucleotide. The amount of EKLF bound tothe polynucleotide is determined using a band-shift assay.

In particular embodiments, an EKLF polypeptide, e.g., a human EKLFprotein, is contacted with a candidate agent before or during an invitro transcription assay using a reporter gene operably lined to apromoter or enhancer element bound by EKLF under conditions and for atime sufficient to allow transcription of the reporter gene. The amountof transcribed reporter mRNA or protein may be determined usingquantitative PCR or by detection of the reporter protein, e.g., byfluorescence if a fluorescence report or by using an antibody that bindsthe reporter protein.

In certain embodiments, a cell comprising an EKLF polypeptide, e.g., ahuman EKLF protein, is contacted with a candidate agent for a timesufficient for the EKLF to have activated or repressed any target genes,and then the amount of target gene expressed is determined by measuringtarget gene mRNA or encoded protein levels, e.g., by quantitative PCR oran immunoassay using an antibody specific for the target gene.

In certain embodiments that include measuring nuclear translocation ofEKLF, the candidate agent is determined to be an active agent if theamount of the EKLF polypeptide contacted with the candidate agentpresent in the cytoplasm is less than 90%, less than 80%, less than 70%,less than 60%, less than 50%, less than 40%, less than 30%, less than20%, less than 10%, or 0% as compared to the amount of an EKLFpolypeptide not contacted with the candidate agent in the cytoplasm. Incertain embodiments, the candidate agent is determined to be an activeagent if the amount of the EKLF polypeptide present in the cytoplasm isless than or equal to a pre-determined cut-off value, which may bedetermined based on the amounts observed in the cytoplasm inmegakaryocyte/erythroid precursor cells, mature erythrocytes, cells at adifferentiation stage before, during or following the CFU-E/Pro-E toBaso-E transition, or sorted CFU-E/ProE, Baso-E, PolyCh-E, or OrthoCh-Ecells. In particular embodiments, the pre-determined cut-off value is80%, 50% or 10%. In certain embodiments that include measuring nucleartranslocation of EKLF, the candidate agent is determined to be an activeagent if the amount of the EKLF polypeptide contacted with the candidateagent present in the nucleus is greater than 90%, greater than 80%,greater than 70%, greater than 60%, greater than 50%, greater than 40%,greater than 30%, greater than 20%, or greater than 10%, as compared tothe amount of an EKLF polypeptide not contacted with the candidate agentin the nucleus. In certain embodiments, the candidate agent isdetermined to be an active agent if the amount of the EKLF polypeptidepresent in the nucleus is less than or equal to a pre-determined cut-offvalue, which may be determined based on the amounts observed in thenucleus in Baso-E. In particular embodiments, the pre-determined cut-offvalue is 80%, 50% or 10%.

In certain embodiments that include measuring transactivator activity ofEKLF, the candidate agent is determined to be an active agent if theamount of the target gene expressed in the presence of an EKLFpolypeptide that was contacted with the candidate agent being examinedis less than 90%, less than 80%, less than 70%, less than 60%, less than50%, less than 40%, less than 30%, less than 20%, less than 10%, or 0%as compared to the amount of the target gene expressed in the presenceof an EKLF polypeptide not contacted with the candidate agent. Incertain embodiments that include measuring repressor activity of EKLF,the candidate agent is determined to be an active agent if the amount ofthe target gene expressed in the presence of an EKLF polypeptide thatwas contacted with the candidate agent being examined is increased by atleast 10%, at least 20%, at least 30%, at least 40%, at least 50%, atleast 60%, at least 70%, at least 100%, at least 200%, at least 500%, orat least 1000% as compared to the amount of the target gene expressed inthe presence of an EKLF polypeptide not contacted with the candidateagent.

In other embodiments, a method of identifying an active agent capable ofextending the lifespan or health span and/or inhibiting tumorigenesis ortumor metastasis of a subject, comprises: administering a candidateagent to a transgenic animal, e.g., a knock-in animal, described herein;and comparing the lifespan of the transgenic, e.g., knock-in, animalafter the administration of the candidate agent with that of a controlanimal that was not administered the candidate agent, wherein if thelifespan of the transgenic animal that was administered the candidateagent is longer than that of the control animal, then the candidateagent is the active agent capable of extending the lifespan or healthspan and/or inhibiting tumorigenesis or tumor metastasis of the subject.In particular embodiments, the lifespan of the animal treated with anactive agent is extended by at least 5%, at least 10%, at least 20%, atleast 30%, at least 40%, at least 50%, at least 60%, at least 70%, atleast 80%, at least 90%, or at least 100% as compared to the lifespan ofan animal not treated with the active agent. In particular embodiments,the transgenic animal is a non-human mammal knock-in wherein both EKLFalleles have been modified to reduce sumoylation at Lys74 orphosphorylation at Ser68. In particular embodiments, both EKLF allelescomprise an amino acid substation in place of Lys74 or Ser68. Inparticular embodiments, the amino acid substitution is K74R.

The candidate agent can be administered to the animal in any mannerdesired and/or appropriate for delivery of the agent in order to examinethe increasing longevity activity or reduced tumorigenesis. For example,the candidate agent can be administered by injection (e.g., byintravenously, intramuscularly, subcutaneously injection), infusion,orally, or any other suitable means.

Administration of a candidate agent to an animal may involveadministering varying amounts of the candidate agent, and may includedelivery of the agent in different formulations and routes. The abilityof a candidate agent to halt or slow down a normal aging process can beassessed by administering the candidate agent to the animal, e.g.,transgenic animal, and evaluating its effect on the lifespan of thetransgenic animal. The ability of a candidate agent to prevent aging canbe assessed by administering the candidate agent to a wild-type animalor without induction of the EKLF K74R mutation that results in enhancedlifespan.

In another embodiment, the present invention provides a method ofidentifying candidate targets for increasing longevity, life span orhealth span, or reducing tumorigenesis or tumor metastasis, thatincludes: measuring the expression level in a wild-type animal (or wildtype cell) of one or more genes regulated by an EKLF polypeptide; andmeasuring the expression level in an animal (or cell) that expresses amodified EKLF polypeptide described herein of the one or more genesregulated by an EKLF polypeptide, wherein genes showing a significantdifference in expression level between the two animals (or cells) areidentified as candidate therapeutic targets. In certain embodiments, thegenes include one or more of the various genes described herein as beingregulated by EKLF. In particular embodiments, the measured expressionlevels are amounts of mRNA transcribed from the one or more genes oramounts of the polypeptide encoded by the one or more genes. Methods ofdetermining amounts of mRNA in a sample are known and available in theart and include, for example, quantitative polymerase chain reaction(qPCR). Methods of determining amounts of a polypeptide in a sample areknown and available in the art and include, for example, ELISA,immunoprecipitation, or FACS, typically using antibodies thatspecifically bind to the encoded polypeptide. In particular embodiments,expression levels of the one or more genes are determined in one or moreparticular cell types of the animals, e.g., bone marrow cells,erythrocytes, blood cells, erythrocyte and/or megakaryocyte progenitorcells, or multipotent progenitor cells. Such cells may be isolated fromthe animal using procedures known in the art, including, e.g., FACSusing antibodies that bind to specific cell surface markers present onthese cell types. In particular embodiments, the transgenic animal is anon-human mammal knock-in wherein both EKLF alleles have been modifiedto reduce sumoylation at Lys74 or phosphorylation at Ser68. Inparticular embodiments, both EKLF alleles comprise an amino acidsubstation in place of Lys74 or Ser68. In particular embodiments, theamino acid substitution is K74R.

Examples of genes that are regulated by EKLF include but are not limitedto: genes that are upregulated by EKLF such as alpha globin, betaglobin, Epb4.9, Tspo2, Fn3k; and genes that are downregulated by EKLFsuch as Hecw 1, Nrip3, and Jak3. In certain embodiments, genes havinghigher expression in wild type animals (or cells) as compared to themodified EKLF animals (or cells) of the present invention (and theirencoded proteins) are targets for agents that reduce their expression orinhibit their activity, e.g., at the expression level or at the proteinlevel. In certain embodiments, genes having lower expression in wildtype animals (or cells) as compared to the modified EKLF animals (orcells) of the present invention (and their encoded proteins) are targetsfor agents that increase their expression or increase their activity,such as gene therapy vectors.

In particular embodiments of methods of identifying an active agentbased on different amounts of expression of genes or their encodedproteins, the method further comprises identifying agents known tomodulate the expression or activity of a gene or encoded proteinidentified as being differentially expressed in wild type animals orcells as compared to modified EKLF animals or cells. Such agents may beidentified by a variety of means, including, e.g., reference toscientific publications or databases that include information on howcertain chemical compounds affect the expression of specific genes, orbased on the known functional activity of the differentially expressedprotein.

In one embodiments, the present invention includes a method ofidentifying an active agent capable of increasing longevity and/orinhibiting tumorigenesis or tumor metastasis of a subject, comprising:contacting a cell capable of expressing a modified EKLF allele encodinga modified EKLF polypeptide comprising one or more amino acidmodifications as compared to a wild-type EKLF polypeptide with acandidate agent; and measuring the expression level of the modified EKLFpolypeptide, wherein if the expression level of the modified EKLFpolypeptide is higher than the expression level in a control cell notcontacted with the candidate agent, the candidate agent is an activeagent capable of increase longevity and/or inhibiting tumorigenesis ofthe subject.

In certain embodiments, any of the methods for identifying an activeagent described herein further comprise one or more additional steps,e.g., to confirm or validate that the candidate agent has the desiredeffect on a mammal. In one embodiment, the methods further includeproviding an identified active agent to a mammal and determining whetherthe mammal has one or more characteristics associated with increasedlongevity, increased life span or increased health span, as compared toa mammal not treated with the active agent. Examples of suchcharacteristics include reduced graying of the hair, increased motorcoordination, increased muscle strength, reduced osteoporosis, greaterbone volume, increased bone density, greater trabecular number, orreduced trabecular spacing, e.g., as compared to untreated mammals ofthe same age. In addition, cellular changes associated with aging may beexamined, or changes in tissue or organ structure or function may beexaminer. In one embodiment, the methods further include providing anidentified active agent to a mammal and determining whether the mammalhas one or more characteristics associated with reduced tumorigenesis ortumor metastasis, as compared to a mammal not treated with the activeagent.

In particular embodiments of any of the screening assays, the EKLFpolypeptide is a wild type EKLF polypeptide or a fragment thereofcapable of being phosphorylated and/or sumoylated. In certainembodiments, a fragment comprises a stretch of at least 10%, at least20%, at least 30%, at least 40%, at least 50%, at least 70%, at least80%, or at least 90% of the contiguous amino acids of an EKLFpolypeptide. In particular embodiments, an EKLF polypeptide has at least80%, at least 85%, at least 90%, at least 95%, or at least 98% identityto a wild-type EKLF polypeptide or fragment thereof In particularembodiments, a wild type EKLF polypeptide is a mammalian EKLF, such as amouse, human, rat or rabbit EKLF polypeptide, including but not limitedto any of those described herein. In certain embodiments, the EKLFpolypeptide is a modified EKLF polypeptide, including but not limited toan EKLF polypeptide comprising an amino acid modification, e.g.,substitution, at a sumoylation site or phosphorylation site describedherein. In particular embodiments, the EKLF polypeptide is endogenous tothe cell, whereas in other embodiments, the EKLF polypeptide isexogenous to the cell or has been introduced into the cell. Inparticular embodiments, the cell comprises an exogenous nucleic acidcapable of expressing the EKLF polypeptide. In particular embodiments,the cell is a transgenic cell described herein or derived from atransgenic animal described herein.

The candidate agents that can be screened for increasing longevityactivity or reduced tumorigenesis activity, e.g., using the non-humantransgenic animal model established herein, include, without limitation,synthetic, naturally occurring, or recombinantly produced molecules,including small molecules, peptides, antibodies, and polypeptides.Candidate agents can be obtained from a wide variety of sourcesincluding libraries of synthetic or natural compounds. For example, thecandidate agents can be obtained using any of the numerous approaches incombinatorial library methods known in the art, including biologicallibraries, spatially addressable parallel solid phase or solution phaselibraries; synthetic library methods requiring deconvolution, the‘one-bead one compound’ library method, and synthetic library methodusing affinity chromatography selection. The biological library approachincludes peptide libraries, while other approaches are applicable topeptide, non-peptide oligomers or small molecule libraries of compounds.

In certain embodiments, active agents (and candidate agents) are smallorganic compounds, peptides, proteins, polynucleotides, non-peptidecompounds, synthetic compounds, fermentation products, or cell extracts.In certain embodiments, small organic compounds have a molecular weightof more than 50 and less than about 20,000 daltons. In particularembodiments, proteins are antibodies or fragments thereof, such as scFv,nobodies, etc. In particular embodiments, an active agent is an antibodyor fragment thereof that binds to EKLF, thus preventing itsphosphorylation at Ser68 and/or sumoylation at Lys74. In certainembodiments, the antibody or fragment thereof binds to a region of EKLFthat comprises or overlaps with a region of amino acid residues 68-74 ofEKLF.

In certain embodiments, polynucleotides are DNA or RNA, eithersingle-stranded or double-stranded, and including modified formsthereof, including those having modified nucleobases and/or modifiedinternucleoside linkages, e.g., to enhance stability or increasepotency. In certain embodiments, polynucleotides bind to and/or inhibitexpression or translation of an EKLF gene or mRNA. In certainembodiments, polynucleotides are RNA interfering agents, siRNA, shRNA,multivalent siRNA, or miRNA. Polynucleotides that bind to an EKLF geneor mRNA may be designed based on available computer modeling programs,which identify optimal target regions within a gene or mRNA (see, e.g.,Halo-Bio RNAi Therapeutics, Seattle, Wash.). In particular embodiments,a polynucleotide agent comprises a region of homology to or a regioncomplementary to an EKLF DNA or mRNA sequence, e.g., a homologous orcomplementary region of at least 6 nucleotides, at least 8 nucleotides,at least 12 nucleotides, at least 16 nucleotides, at least 24nucleotides, or at least 30 nucleotides. In particular embodiments,candidate agents are compounds known to decrease or inhibitphosphorylation or sumoylation.

In particular embodiments, an assay described herein is used to screen alibrary comprising a plurality of candidate agents in order to identifyan active agent. In particular embodiments, the library comprises aplurality of small organic compounds, peptides, proteins, orpolynucleotides. A variety of libraries of small organic compounds areknown and commercially available, which may be used according to thepresent invention.

Methods for Enhancing Longevity, Lifespan, or Health Span, and ReducingTumorgenisis or Tumor Metastasis

The present invention further provides methods for increasing longevity,life span or health span of a subject, as well as methods for inhibitingtumorigenesis or tumor metastasis of a subject in need thereof. As shownin the accompanying Examples, it has been unexpectedly demonstrated thatmodification of the sumoylation site of the EKLF polypeptide in a mammalresults in increased longevity, increased life span and increased healthspan of the mammal, as well as reduced tumorigenesis and reduced tumormetastasis in the mammal. In addition, the role of the EKLF K74Rmodification on cancerous cells was tested in melanoma bearing mice.Surprisingly, the expression of EKLF K74R allele prevented the cancerousmelanoma cells from metastasizing. Accordingly, one further aspect ofthe present disclosure is to provide a method of treating a subjectsuffering from a cellular proliferative disorder. Without wishing to bebound to any particular theory, it is believed that modification of thesumoylation site inhibits or destroys sumoylation of the EKLFpolypeptide, which alters its activity in a manner resulting inincreased longevity and health, as well as reduced tumorigenesis andtumor metastasis.

Accordingly, the present invention includes methods for increasing orenhancing longevity, life span or health span of a subject, as well asmethods for inhibiting tumorigenesis or tumor metastasis, which includeproviding a modified EKLF polypeptide of the invention to the subject,and/or providing a first agent that alters an activity of an endogenousor wild-type EKLF polypeptide to the subject. In certain embodiments, asecond agent that reduces the activity or expression of endogenous,wild-type EKLF polypeptides in the subject is also be provided to thesubject. In particular embodiments, a subject is a mammal, e.g., a humanor non-human mammal. The first active agent, second active agent and/ormodified EKLF polypeptide may be provided to the subject in an effectiveamount. The modified EKLF polypeptide by be provided by administering amodified EKLF polypeptide or a polynucleotide encoding the modified EKLFpolypeptide to the subject. In particular embodiments, the modified EKLFpolypeptide is a modified human EKLF polypeptide. In particularembodiments, it comprises a mutation that inhibits sumoylation, Incertain embodiments, it comprises a modification of Lys54. These methodsmay also be used to achieve, or retain for a longer period of time, aspecific phenotype or characteristic associated with youthfulness orincreased longevity, including any of those described or demonstratedherein, such as reduced graying of the hair, increased motorcoordination, increased muscle strength, reduced osteoporosis, greaterbone volume, greater bone density, greater trabecular number, or reducedtrabecular spacing, e.g., as compared to untreated subjects of the sameage.

In particular embodiments, the subject is a mammal, e.g., a human. Incertain embodiments, the subject has been diagnosed with or isconsidered at risk of developing a tumor or a tumor metastasis. Inparticular embodiments, the subject has been diagnosed with or isconsidered at risk of developing a disease or disorder associated withaging. In certain embodiments, the subject is at least 20 years old, atleast 30 years old, at least 40 years old, at least 50 years old, atleast 60 years old, at least 70 years old, or at least 80 years old.

In one embodiment, the present invention includes a method of treatingor preventing a cellular proliferative disorder (e.g., tumorigenesis ortumor metastasis) in a subject in need thereof, comprising administeringto the subject an effective amount of a polypeptide, or a nucleic acidencoding the polypeptide, wherein the polypeptide is a modified EKLFpolypeptide comprising one or more amino acid modifications that conferdecreased sumoylation and/or decreased nuclear translocation of themodified EKLF polypeptide as compared to a wild-type EKLF polypeptide.In certain embdoimetns, the modified EKLF polypeptide is a modifiedhuman EKLF polypeptide. In certain embodiments, the modified EKLFpolypeptide has decreased sumoylation as compared to the wild-type EKLFpolypeptide. In certain embodiments, the modified EKLF polypeptide hasreduced translocation from the cytoplasm to the nucleus as compared tothe wild-type EKLF polypeptide. In certain embodiments, the modifiedEKLF polypeptide has a modified transactivator activity or a modifiedrepressor activity as compared to the wild-type EKLF polypeptide. Invarious embodiments, the one or more amino acid modifications comprisesa modification at an amino acid position that is sumoylated orphosphorylated in the wild-type EKLF polypeptide, such as a modificationof an amino acid at position 74 of the full length mouse wild-type EKLFpolypeptide, e.g., substitution of Lys with Arg (K74R), or amodification of an amino acid at position 54 of the full length humanwild-type EKLF polypeptide, e.g., substitution of Lys with Arg (K54R),or a modification of an amino acid at position 68 of the full lengthwild-type EKLF polypeptide. One method includes administering to thesubject an effective amount of a polypeptide or a nucleic acid encodingthe polypeptide, wherein the polypeptide is a modified human EKLF, inwhich the lysine residue at position 54 is mutated, optionally toarginine. in particular embodiments, the modified human EKLF is notsumoylated at position 54.

Polypeptides may be administered to a subject in a variety of manner,including as “naked” polypeptides or complexed with a delivery-enhancingagent. In particular embodiments, a polypeptide is associated with anagent that enhances cellular uptake. Nucleic acids may be administeredto a subject in a variety of manners, including as “naked” DNA or RNA,or complexed with lipids or encapsulated in a lipid particle. Inparticular embodiments wherein a nucleic acid, i.e., a polynucleotide,is administered to the subject, the nucleic acid is present in anexpression vector. In certain embodiments, the nucleic acid is presentin a viral vector. The viral vector may be a replication defective orreplication competent viral vector. In various embodiments, the viralvector is derived from a herpes virus, a retrovirus, a lentivirus, avaccinia virus, an attenuated vaccinia virus, a canary pox virus, anadenovirus, or an adeno-associated virus. The nucleic acid may bepresent in an expression vector, in which the nucleic acid sequenceencoding the modified EKLF polypeptide is operatively linked to apromoter or enhancer-promoter combination. Suitable expression vectorsinclude plasrnids and viral vectors such as herpes viruses,retroviruses, vaccinia viruses, attenuated vaccinia viruses, canary poxviruses, adenoviruses and adeno-associated viruses. In particularembodiments, the nucleic acid is operably linked to a promoter sequenceand, optionally enhancer elements. In particular embodiments, thepromoter and/or enhancer elements confer tissue-specific expression ofthe nucleic acid and its encoded polypeptide. In particular embodiments,the promoter and/or enhancer elements are EKLF gene promoter and/orenhancer elements, and confer a similar or the same expression patternto the nucleic acid as endogenous EKLF.

The above-mentioned nucleic acids or polynucleotide can be delivered bythe use of polymeric, biodegradable microparticle or microcapsuledelivery devices known in the art. Another way to achieve uptake of thenucleic acid in a host is using liposomes, prepared by standard methods.The polynucleotide can be incorporated alone into these deliveryvehicles or co-incorporated with tissue-specific antibodies.Alternatively, one can prepare a molecular conjugate composed of aplasmid or other vector attached to poly-L-lysine by electrostatic orcovalent forces. Poly-L-lysine binds to a ligand that can bind to areceptor on target cells (Cristiano, et al., 1995, J. Mol. Med. 73:479).Alternatively, tissue specific targeting can be achieved by the use oftissue-specific transcriptional regulatory elements that are known inthe art. Delivery of “naked DNA” (i.e., without a delivery vehicle) toan intramuscular, intradermal, or subcutaneous site is another means toachieve in vivo expression.

The polypeptide can be synthesized using methods known in the art or beprepared using recombinant technology. For example, one can clone anucleic acid encoding the polypeptide (e.g., the modified EKLF havingK74R mutation) in an expression vector, in which the nucleic acid isoperably linked to a regulatory sequence suitable for expressing thepolypeptide in a host cell. One can then introduce the vector into asuitable host cell to express the polypeptide. The expressed recombinantpolypeptide can be purified from the host cell by methods such asammonium sulfate precipitation and fractionation column chromatography.A polypeptide thus prepared can be tested for its activity according tothe methods described herein.

In certain embodiments wherein the polypeptide or the nucleic acid isadministered to the subject, the methods further comprise administeringto the subject a second active agent that inhibits expression of theendogenous EKLF polypeptide. In particular embodiments, the secondactive agent is a nucleic acid molecule, optionally an antisense RNA,siRNA, shRNA or miRNA that binds an mRNA or complement thereof thatencodes the endogenous EKLF polypeptide.

In one embodiment, the present invention includes a method of treatingor preventing a cellular proliferative disorder (e.g., tumorigenesis ortumor metastasis) in a subject in need thereof, comprising administeringto the subject an effective amount of an active agent that inhibitssumoylation of the endogenous EKLF polypeptide and/or reducestranslocation of the endogenous EKLF polypeptide from the cytoplasm tothe nucleus. In one embodiment, the active agent inhibits sumoylation.In one embodiment, the active agent reduces translocation.

In one embodiment, the present invention includes a method of treatingor preventing a cellular proliferative disorder (e.g., tumorigenesis ortumor metastasis) in a subject in need thereof, comprising administeringto the subject an effective amount of an active agent that alters one ormore activities of the endogenous EKLF polypeptide. In one embodiment,the active agent inhibits sumoylation. In one embodiment, the activeagent reduces translocation. In certain embodiments, the active agentmodifies a transactivator activity or modifies a repressor activity ofthe endogenous EKLF polypeptide.

In particular embodiments, active agents used in methods of the presentinvention bind to the endogenous EKLF polypeptide. In particularembodiments, an active agent is a small organic molecule or apolypeptide, optionally an antibody or functional fragment thereof.

Methods of the present invention may be used to treat or prevent avariety of cellular proliferative disorders, including but not limitedto tumors and tumor metastases, including but not limited to any ofthose described herein. In particular embodiments, the tumor or tumormetastasis is a liver cancer, a colon cancer, a breast cancer, aprostate cancer, a hepatocellular carcinoma, a melanoma, a lung cancer,a glioblastoma, a brain tumor, a hematopoetic malignancy, aretinoblastoma, a renal cell carcinoma, a head and neck cancer, acervical cancer, a pancreatic cancer, an esophageal cancer, or asquamous cell carcinoma.

In particular embodiments, methods of treating or preventing aproliferative disorder further comprise administering to the subject aneffective amount of an anti-proliferation agent for treating thecellular proliferative disorder. In particular embodiments, theanti-proliferation agent is an alkylating agent, a topoisomeraseinhibitor, an anti-metabolite, or a cytotoxicity antibiotic. In someembodiments, the alkylating agent is cisplatin, carboplatin,oxaliplatin, mechlorethamine, cyclophosphamide, melphalan, chlorambucil,ifosfamide, busulfan, N-nitroso-N- methylurea (MNU), carmustine,lomustine, semustine, fotemustine, streptozotocin, dacarbazine,mitozolomide, temozolomide, thiotepa, mytomycin, or diaziquone. In someembodiments, the topoisomerase inhibitor is camptothecin, irinotecan,topotecan, etoposide, doxorubicin, teniposide, novobiocin, merbarone, oraclarubicin. In some embodiments, the anti-metabolite is fluoropymidine,deoxynucleoside analogue, thiopurine, methotrexate, or pemetrexed.Insome embodiments, the cytotoxicity antibiotic is actinomycin, bleomycin,plicamycin, mitomycin, doxorubicin, daunorubicin, epirubicin,idarubicin, piraubicin, alcarubicin, or mitoxantrone.

In other embodiments, the present invention includes a method ofextending the lifespan or health span of a subject, comprisingadministering to the subject an effective amount of a polypeptide, or anucleic acid encoding the polypeptide, wherein the polypeptide is amodified EKLF polypeptide comprising one or more amino acidmodifications that confer decreased sumoylation and/or decreased nucleartranslocation of the modified EKLF polypeptide as compared to awild-type EKLF polypeptide. In certain embodiments, the modified EKLFpolypeptide has decreased sumoylation as compared to the wild-type EKLFpolypeptide. In certain embodiments, the modified EKLF polypeptide hasreduced translocation from the cytoplasm to the nucleus as compared tothe wild-type EKLF polypeptide. In certain embodiments, the modifiedEKLF polypeptide has a modified transactivator activity or a modifiedrepressor activity as compared to the wild-type EKLF polypeptide. Inparticular embodiments, the nucleic acid is present in an expressionvector. In certain embodiments, the nucleic acid is present in a viralvector. In various embodiments, the viral vector is derived from aherpes virus, a retrovirus, a vaccinia virus, an attenuated vacciniavirus, a canary pox virus, an adenovirus, or an adeno-associated virus.In various embodiments, the one or more amino acid modificationscomprises a modification at an amino acid position that is sumoylated orphosphorylated in the wild-type EKLF polypeptide, such as a modificationof an amino acid at position 74 of the full length wild-type EKLFpolypeptide, e.g., substitution of Lys with Arg (K74R), or amodification of an amino acid at position 68 of the full lengthwild-type EKLF polypeptide.

In certain embodiments wherein the polypeptide or the nucleic acid isadministered to the subject, the methods further comprise administeringto the subject a second active agent that inhibits expression of theendogenous EKLF polypeptide. In particular embodiments, the secondactive agent is a nucleic acid molecule, optionally an antisense RNA,siRNA, shRNA or miRNA that binds an mRNA or complement thereof thatencodes the endogenous EKLF polypeptide.

In one embodiment, the present invention includes a method of extendingthe lifespan or health span of a subject, comprising administering tothe subject an effective amount of an active agent that inhibitssumoylation of the endogenous EKLF polypeptide and/or reducestranslocation of the endogenous EKLF polypeptide from the cytoplasm tothe nucleus. In one embodiment, the active agent inhibits sumoylation.In one embodiment, the active agent reduces translocation.

In one embodiment, the present invention includes a method of extendingthe lifespan or health span of a subject, comprising administering tothe subject an effective amount of an active agent that alters one ormore activities of the endogenous EKLF polypeptide. In one embodiment,the active agent inhibits sumoylation. In one embodiment, the activeagent reduces translocation. In certain embodiments, the active agentmodifies a transactivator activity or modifies a repressor activity ofthe endogenous EKLF polypeptide.

The present invention further includes pharmaceutical compositionscomprising a polynucleotide encoding a modified EKLF, a modified EKLFpolypeptide, a candidate agent, or an active agent, and one or morepharmaceutically acceptable excipients, diluents or carriers. Methods ofthe present invention may be performed using pharmaceutical compositioncomprising any of these. Embodiments of the present invention includecompositions comprising modified EKLF polypeptide, polynucleotidesencoding modified EKLF polypeptides, or active agents formulated inpharmaceutically-acceptable or physiologically-acceptable solutions foradministration to a cell, subject, or an animal, either alone, or incombination with one or more other modalities of therapy. It will alsobe understood that, if desired, the compositions of the invention may beadministered in combination with other agents as well, such as, e.g.,other proteins or polypeptides or various pharmaceutically-activeagents. There is virtually no limit to other components that may also beincluded in the compositions, provided that the additional agents do notadversely affect the modulatory or other effects desired to be achieved.

In the pharmaceutical compositions of the invention, formulation ofpharmaceutically-acceptable excipients and carrier solutions iswell-known to those of skill in the art, as is the development ofsuitable dosing and treatment regimens for using the particularcompositions described herein in a variety of treatment regimens,including e.g., oral, parenteral, intravenous, intranasal, andintramuscular administration and formulation.

In certain circumstances it will be desirable to deliver thepharmaceutical compositions disclosed herein parenterally,subcutaneously, intravenously, intramuscularly, intra-arterially,intrathecally, intraparenchymally, intracisternally,intraventricularlly, intraurethrally, intrasternally, intracranially,intrasynovially, or even intraperitoneally as described, for example, inU.S. Pat. Nos. 5,543,158; 5,641,515 and 5,399,363 (each specificallyincorporated herein by reference in its entirety). Suitable devices forparenteral administration include needle (including microneedle)injectors, needle-free injectors, and infusion techniques.

Solutions of the active compounds as free base or pharmacologicallyacceptable salts may be prepared in water suitably mixed with asurfactant, such as hydroxypropylcellulose. Dispersions may also beprepared in glycerol, liquid polyethylene glycols, and mixtures thereofand in oils. Under ordinary conditions of storage and use, thesepreparations contain a preservative to prevent the growth ofmicroorganisms.

The pharmaceutical forms suitable for injectable use include sterileaqueous solutions or dispersions and sterile powders for theextemporaneous preparation of sterile injectable solutions ordispersions (U.S. Pat. No. 5,466,468, specifically incorporated hereinby reference in its entirety). In all cases the form should be sterileand should be fluid to the extent that easy syringability exists. Itshould be stable under the conditions of manufacture and storage andshould be preserved against the contaminating action of microorganisms,such as bacteria and fungi. The carrier can be a solvent or dispersionmedium containing, for example, water, ethanol, polyol (e.g., glycerol,propylene glycol, and liquid polyethylene glycol, and the like),suitable mixtures thereof, and/or vegetable oils. Proper fluidity may bemaintained, for example, by the use of a coating, such as lecithin, bythe maintenance of the required particle size in the case of dispersionand by the use of surfactants. The prevention of the action ofmicroorganisms can be facilitated by various antibacterial andantifungal agents, for example, parabens, chlorobutanol, phenol, sorbicacid, thimerosal, and the like. In many cases, it will be preferable toinclude isotonic agents, for example, sugars or sodium chloride.Prolonged absorption of the injectable compositions can be brought aboutby the use in the compositions of agents delaying absorption, forexample, aluminum monostearate and gelatin.

For parenteral administration in an aqueous solution, for example, thesolution should be suitably buffered if necessary and the liquid diluentfirst rendered isotonic with sufficient saline or glucose. Theseparticular aqueous solutions are especially suitable for intravenous,intramuscular, subcutaneous and intraperitoneal administration. In thisconnection, a sterile aqueous medium that can be employed will be knownto those of skill in the art in light of the present disclosure. Forexample, one dosage may be dissolved in 1 ml of isotonic NaCl solutionand either added to 1000 ml of hypodermoclysis fluid or injected at theproposed site of infusion (see, e.g., Remington's PharmaceuticalSciences, 15th Edition, pp. 1035-1038 and 1570-1580). Some variation indosage will necessarily occur depending on the condition of the subjectbeing treated. The person responsible for administration will, in anyevent, determine the appropriate dose for the individual subject.Moreover, for human administration, preparations should meet sterility,pyrogenicity, and the general safety and purity standards as required byFDA Office of Biologics standards.

Sterile injectable solutions can be prepared by incorporating the activecompounds in the required amount in the appropriate solvent with thevarious other ingredients enumerated above, as required, followed byfiltered sterilization. Generally, dispersions are prepared byincorporating the various sterilized active ingredients into a sterilevehicle which contains the basic dispersion medium and the requiredother ingredients from those enumerated above. In the case of sterilepowders for the preparation of sterile injectable solutions, thepreferred methods of preparation are vacuum-drying and freeze-dryingtechniques which yield a powder of the active ingredient plus anyadditional desired ingredient from a previously sterile-filteredsolution thereof.

The compositions disclosed herein may be formulated in a neutral or saltform. Pharmaceutically-acceptable salts, include the acid addition salts(formed with the free amino groups of the protein) and which are formedwith inorganic acids such as, for example, hydrochloric or phosphoricacids, or such organic acids as acetic, oxalic, tartaric, mandelic, andthe like. Salts formed with the free carboxyl groups can also be derivedfrom inorganic bases such as, for example, sodium, potassium, ammonium,calcium, or ferric hydroxides, and such organic bases as isopropylamine,trimethylamine, histidine, procaine and the like. Upon formulation,solutions will be administered in a manner compatible with the dosageformulation and in such amount as is therapeutically effective. Theformulations are easily administered in a variety of dosage forms suchas injectable solutions, drug-release capsules, and the like.

As used herein, “carrier” includes any and all solvents, dispersionmedia, vehicles, coatings, diluents, antibacterial and antifungalagents, isotonic and absorption delaying agents, buffers, carriersolutions, suspensions, colloids, and the like. The use of such mediaand agents for pharmaceutical active substances is well known in theart. Except insofar as any conventional media or agent is incompatiblewith the active ingredient, its use in the therapeutic compositions iscontemplated. Supplementary active ingredients can also be incorporatedinto the compositions.

The phrase “pharmaceutically-acceptable” refers to molecular entitiesand compositions that do not produce an allergic or similar untowardreaction when administered to a human. The preparation of an aqueouscomposition that contains a protein as an active ingredient is wellunderstood in the art. Typically, such compositions are prepared asinjectables, either as liquid solutions or suspensions; solid formssuitable for solution in, or suspension in, liquid prior to injectioncan also be prepared. The preparation can also be emulsified.

In certain embodiments, the delivery may occur by use of liposomes,nanocapsules, microparticles, microspheres, lipid particles, vesicles,and the like. In particular, the compositions of the present inventionmay be formulated for delivery either encapsulated in a lipid particle,a liposome, a vesicle, a nanosphere, a nanoparticle or the like. Theformulation and use of such delivery vehicles can be carried out usingknown and conventional techniques.

In certain embodiments, the agents provided herein may be attached to apharmaceutically acceptable solid substrate, including biocompatible andbiodegradable substrates such as polymers and matrices. Examples of suchsolid substrates include, without limitation, polyesters, hydrogels (forexample, poly(2-hydroxyethyl-methacrylate), or poly(vinylalcohol)),polylactides (U.S. Pat. No. 3,773,919), copolymers of L-glutamic acidand γ-ethyl-L-glutamate, non-degradable ethylene-vinyl acetate,degradable lactic acid-glycolic acid copolymers such aspoly(lactic-co-glycolic acid) (PLGA) and the LUPRON DEPOT™ (injectablemicrospheres composed of lactic acid-glycolic acid copolymer andleuprolide acetate), poly-D-(-)-3-hydroxybutyric acid, collagen, metal,hydroxyapatite, bioglass, aluminate, bioceramic materials, and purifiedproteins.

Methods of formulation are well known in the art and are disclosed, forexample, in Remington: The Science and Practice of Pharmacy, MackPublishing Company, Easton, Pa., 19th Edition (1995). The compositionsand agents provided herein may be administered according to the methodsof the present invention in any therapeutically effective dosing regime.The dosage amount and frequency are selected to create an effectivelevel of the agent without harmful effects. The effective amount of acompound of the present invention will depend on the route ofadministration, the type of warm-blooded animal being treated, and thephysical characteristics of the specific warm-blooded animal underconsideration. These factors and their relationship to determining thisamount are well known to skilled practitioners in the medical arts. Thisamount and the method of administration can be tailored to achieveoptimal efficacy but will depend on such factors as weight, diet,concurrent medication and other factors which those skilled in themedical arts will recognize.

Embodiments of the present invention, in other aspects, provide kitscomprising one or more containers filled with one or more pharmaceuticalcompositions of the polypeptides, polynucleotides, active agents, etc.,of the invention, as described herein. The kits can include writteninstructions on how to use such compositions (e.g., to enhancelongevity, life span or health span, or to inhibit or reducetumorigenesis or tumor metastasis).

The kits herein may also include one or more additional therapeuticagents or other components suitable or desired for the indication beingtreated, or for the desired diagnostic application. An additionaltherapeutic agent may be contained in a second container, if desired.Examples of additional therapeutic agents include, but are not limitedto anti-neoplastic agents.

The kits herein can also include one or more syringes or othercomponents necessary or desired to facilitate an intended mode ofdelivery (e.g., stents, implantable depots, etc.).

EXAMPLES

Materials and Methods

Experimental Animals

Adult C57BL mice (18 to 25g) were obtained from the National LaboratoryAnimal Center in Taiwan. All mice were maintained in the animal facilityin accordance with the procedures approved by the Experimental AnimalCommittee, Academia Sinica (Taiwan, R.O.C.).

Generation of the EKLF (K74R) Knock-In Mice

Knock-in mice were generated by introducing the sumoylation sitemutation (K74R) of EKLF into the 2nd exon of the mouse EKLF (klf1) genethrough homologous recombination in ES cells by a standardgene-targeting approach using the Cre-loxP recombination system, thetargeting BAC Clone RP24-319P23 (Invitrogen) and the counter-selectionBAC modification Kit (Gene brides). Using mouse genomic DNA from C57B/6JES cells as template, a fragment containing portions of EKLF exon 2 wasPCR amplified and used for constructing a target vector. Prior tocloning into the template targeting vector, codon 74 encoded by exon 2was mutated to code for arginine (K74R) using standard mutagenesistechniques. A neomycin cassette was also constructed into the targetvector, in which a PGK-gb2-neo template encodes the neomycin/kanamycinresistance gene which combines a prokaryotic promoter (gb2) forexpression of kanamycin resistance in E. coli with a eukaryotic promoter(PGK) for expression of neomycin resistance in mammalian cells. Inaddition, the modified wild-type DNA was flanked by ‘loxP’ sites tofacilitate its removal (FIG. 1A). The loxP-PGK-loxP cassette wasinserted at intron 1 of the EKLF gene. The target construct was thenelectroporated into C57B/6J ES cells and selected for neomycinresistance. Appropriately targeted ES clones were identified by 5′ and3′ Southern blotting. Following removal of the neo cassette andconfirmation of the architecture of the modified genomic region encodingEKLF K74R, the ES clones were injected into blastocytes to generatechimera mice. To obtain heterozygous mice containing the knock-inallele, the germline transmitting F1 lines were crossed with Ella-Cremice expressing the Cre recombinase in the whole body. Theeklfheterozygotes carrying one allele containing the point mutation wereintercrossed to achieve the homozygous eklf (K74R) knock-in mice.

The EKLF K74R knock-in targeting vector sequence is shown in Table E1below. The sequence is listed in the order from 5′ to 3′, and thenucleotide positions are numbered in the 5′ to 3′ direction with thefirst 5′ nucleotide numbered as 1. Regions of the targeting vector, e.g.exons and introns of the EKLF gene, loxP sites, PolyA sites, Neo, andthe PGK promoter are indicated by their nucleotide region, i.e. therange of nucleotide positions that the region spans.

TABLE E1 Targeting Vector Polynucleotide Sequence VectorGTGGGCAGACAGGAGCCCTCCAAGAAACTTTCCTAGCCTCATAGCCCATGAGGCA SEQ ID NO: 8GAAGAGAGAGAGGAGGCCTGAGGTCCAGGGTGGACACCAGCCAGCCATGGCCTCAGCTGAGACTGTCTTACCCTCCATCAGTACACTCACCACCCTGGGACAGTTCCTGGACACCCAGGAGGACTTCCTCAAGGTGGGGCCAGTGTGAGTGTGTGGGAGGGGGCAGGTGGTCTTGCATAGGGCATAGTGCTTAGGGGTGGGGCGTCTATCTTACTTTAATATCCTCTGCTCTGTTTTTTGGGGGTGGAGGAGTGGGAGAGCCTCTGAGCCTTGTTTGGGGGAGATGTTCTAGGGGTCTGAGATCAAGGTGAGGTGACACTATAGAATACTCAAGCTATCGAGATAACTTCGTATAATGTATGCTATACGAAGTTATCGCGCCGCACACAAAAACCAACACACAGATCATGAAAATAAAGCTCTTTTATTGGTACCGAATTCGCCAGGGAGCTCTCAGACGTCGCTTGGTCGGTCTTTATTCGAACCCCAGAGTCCCGCTCAGAAGAACTCGTCAAGAAGGCGATAGAAGGCGATGCGCTGCGAATCGGGGGCGGCGATACCGTAAAGCACGAGGAAGCGGTCAGCCCATTCGCCGCCAAGCTCTTCAGCAATATCACGGGTAGCCAACGCTATGTCCTGATAGCGGTCCGCCACACCCAGCCGGCCACAGTCGATGAATCCAGAAAAGCGGCCATTTTCCACCATGATATTCGGCAAGCAGGCATCGCCATGGGTCACGACGAGATCCTCGCCGTCGGGCATGCGCGCCTTGAGCCTGGCGAACAGTTCGGCTGGCGCGAGCCCCTGATGCTCTTCGTCCAGATCATCCTGATCGACAAGACCGGCTTCCATCCGAGTACGTGCTCGCTCGATGCGATGTTTCGCTTGGTGGTCGAATGGGCAGGTAGCCGGATCAAGCGTATGCAGCCGCCGCATTGCATCAGCCATGATGGATACTTTCTCGGCAGGAGCAAGGTGAGATGACAGGAGATCCTGCCCCGGCACTTCGCCCAATAGCAGCCAGTCCCTTCCCGCTTCAGTGACAACGTCGAGCACAGCTGCGCAAGGAACGCCCGTCGTGGCCAGCCACGATAGCCGCGCTGCCTCGTCCTGCAGTTCATTCAGGGCACCGGACAGGTCGGTCTTGACAAAAAGAACCGGGCGCCCCTGCGCTGACAGCCGGAACACGGCGGCATCAGAGCAGCCGATCGTCTGTTGTGCCCAGTCATAGCCGAATAGCCTCTCCACCCAAGCGGCCGGAGAACCTGCGTGCAATCCATCTTGTTCAATGGCCGATCCCATGGTTTAGTTCCTCACCTTGTCGTATTATACTATGCCGATATACTATGCCGATGATTAATTGTCAACACGTGCTGCTGCAGGTCGAAAGGCCCGGAGATGAGGAAGAGGAGAACAGCGCGGCAGACGTGCGCTTTTGAAGCGTGCAGAATGCCGGGCCTCCGGAGGACCTTCGGGCGCCCGCCCCGCCCCTGAGCCCGCCCCTGAGCCCGCCCCCGGACCCACCCCTTCCCAGCCTCTGAGCCCAGAAAGCGAAGGAGCAAAGCTGCTATTGGCCGCTGCCCCAAAGGCCTACCCGCTTCCATTGCTCAGCGGTGCTGTCCATCTGCACGAGACTAGTGAGACGTGCTACTTCCATTTGTCACGTCCTGCACGACGCGAGCTGCGGGGCGGGGGGGAACTTCCTGACTAGGGGAGGAGTAGAAGGTGGCGCGACGGGGCCACCAAAGAACGGAGCCGGTTGGCGCCTACCGGTGGATGTGGAATGTGTGCGAGGCCAGAGGCCACTTGTGTAGCGCCAAGTGCCCAGCGGGGCTGCTAAAGCGCATGCTCCAGACTGCCTTGGGAAAAGCGCCTCCCCTACCCGGTAGAATATAACTTCGTATAATGTATGCTATACGAAGTTATGCGGCCCTAGTGATTTAGGCTCATAGAGACAAAGGTCCAGATAAAGGTGTCCTGGGATTTCCAGGCTTTGAGCTGTAATTTTCTGGGCTATGTGAAGACAGGGAAAGGCTAGGGAAAACGGAGTCGAAGCTGTCCCCTTTGACTCAGAACTCTGCAACCCCTTCTCCCATCCTGAATACTATTCTTGGTAAGTGTCTTAGCTGTCTCTAGCAAGACCTAATGGAGTTGTCTGGAGCTGAGAAAGGGGTTAGGGGAACCGTGTGGGTAAATGACAGGCACCAACGGTGTTTCCAGCCAGGGTTGTTTGAGGGCCAGGTACCCAGTGCCTACCATTCAAGCAGTACGCTCCCTCCCGCAGTGGTGGCGGTCTGAGGAGACGCAGGATTTGGGGCCGGGGCCCCCGAATCCCACGGGGCCGTCCCATCACGTGAGTCTGAGATCGGAGGACCCTTCCGGAGAGGACGATGAGAGGGACGTGACCTGTGCGTGGGACCCGGATCTTTTCCTTACAAACTTTCCAGGTTCCGAGTCTCCCGGCACTTCCCGGACCTGTGCCCTGGCGCCCAGCGTGGGGCCAGTGGCACAGTTCGAGCCGCCTGAGTCTCTGGGCGCCTATGCGGGTGGCCCAGGGTTGGTGACTGGGCCTTTGGGCTCCGAGGAGCACACAAGCTGGGCGCACCCGACTCCGAGACCCCCAGCCCCTGAACCCTTCGTGGCCCCTGCCCTGGCCCCGGGACTCGCTCCCAAGGCTCAGCCCTCGTACTCCGACTCGCGAGCGGGCTCCGTAGGGGGCTTCTTCCCGCGGGCGGGGCTTGCGGTGCCCGCAGCTCCAGGCGCCCCCTATGGGCTGCTGTCGGGATACCCCGCGCTGTACCCCGCGCCACAGTACCAAGGCCACTTCCAGCTCTTTCGCGGGCTCGCGGCGCCTTCTGCTGGTCCCACGGCGCCCCCTTCCTTCTTGAATTGTCTGGGACCTGGGACTGTGGCCACAGAACTCGGGGCCACTGCGATCGCCGGAGACGCAGGCTTGTCCCCGGGAACTGCGCCGCCCAAACGCAGCCGGCGAACTTTGGCACCTAAGAGGCAGGCGGCACATACGTGCGGGCACGAAGGCTGCGGGAAGAGCTACACCAAGAGCTCGCACCTCAAGGCGCACCTGCGCACGCACACGGGTAAGGGCGGGGCCAGACGGGCGGGGGCGGGGCGGGAGCCGCTAGTGAACGAAGGGAGGGGCCGGAGGGTAGTCAGAGGCGTGGCTAAAGGCGGCCCCAGTTCTAGGGGTCGTGAAGACCGCACCTGAGACACTGGGTCAAGTCTAGAAGGGGCGATTCCAGACCCAAATGGGCTAATACAAACACTCGGGAGGCAGAGGCAGGTGGATAGCAGTGACTTCGAGGCCATTTGGGCTATTATAGCGAGTTTCAGCAGCCTGAGCTACTTAGTGAGATCCTGGTTCATAAATAAATAGGTGTAACAGAGGACCTGGGGAACACTTTGGGGACTTCGGTGTTAGAAGTGGATGTGTAAGGCCTGGGTTAGAGATGGGAGAAGAAACTAGAGGGGTGAACCCGAAAGGTACAAGCTTGGAATGCCAGAGCTCAGGATATAGCCAGTATTTACATGCATGCTCGAGCTGGAACCATCTGGGATCAGGAGGTTGAGACACTCAAGTAAAATCAGTTTCAGGGGCAACTGACAGAGGTCCCAGAGTTAAGAAAAGAAGAGAAGGGGGCTGGAGAGATGGCTCAGTGGTTAAGAGCACTGACTGCTCTTCCAGAGGTCCTGAGTTTAAATCCCAGCACCACATGGTGGCTCACAACCATCTGTAATGGGATCCGATGCCCTCTTCTGGTGTGACTGAAGACAGCTACAGTGTACTTACATATAATAAATAAATAAATTAAAAAAAAAAAGAAAGAAAGAAAAAAGAAAAGAAGAGAAGGAAATGCTGAGAGACAGGGCCTAGAAAGAGAAACGGGGTCATCCCAGGACTGGAAGACAGCTGAGGGTCTCCCAAGCATGGCAGGGCACGCAACAGGCTGTAACAGGAAGAGAGGGAATCACCAGAGACAGGGCCTTGAACACTGGGGTGGATTTCTGGGCTTGAACCAAGTTGAGGAACAAGACTGGATATCATCGGGAGGCTCTGCCAGAGCAAGAAATAGCTGCAACGCGGAGAACAAAGAACGAAGGTGCAGCCACATAAAAAGGCAGGGAACTAGCACACCGGAAGTGGGATAGGAGACCGGAAGTGAGAAAACTGCAGGATTGCAGCTGTAGATACAGAAAAGGATTGAGTCACAGAAGGCAGGATTATGTGACCTTTTAACTGTGTGGGCTAGGTATGTCCTAAGACTTGGCTCTACTTCATCAAGGGTGCAAACTGGAGCTGGGTTGCTTGGAGGGTGGTACTTACAGCTCCCTGTCCTTCAGGAGAGAAGCCTTATGCCTGCTCCTGGGACGGCTGTGACTGGAGGTTCGCTCGCTCAGACGAACTGACGCGCCACTACCGGAAGCACACTGGACATCGTCCCTTCTGCTGTGGCCTCTGCCCACGTGCTTTTTCACGCTCTGACCACTTAGCTCTGCACATGAAGCGTCACCTCTGAGTGATCCTGCACAAGGACTGGGGATGAAATAAGAGTGGATCCAAGGACCGTATCCCAAAAGATGGGCCATTATATAGTCCTACCCAGATCAAAAACTGACCAGAAGACCATACAAAGGAGCCTTCAGGACAAACCTCACATGTCCTCAGGGAGCCCCACACATGGCCCCACAGACCCAGCAATATAGACCACCAGATAAATCAACTCAAATGGACCCCTAGACCAGAGGAGTGACCCTGTGTCCTGGACGCAGATGGACTGGGGTGAGATTTCCTAAGATCTAGAAGGGAGCTTCACACTGTGCCCATCTGCTAGGATTGTTGTCGTTACTATAAAAATTTCCCATATAAAACCAG Nucleotide  Region Description of Feature1-4,946 EKLF K74R Knock in Targeting Vector 1-188 Exon 1 of EKLF gene189-368 Intron 1 of EKLF gene 397-431 LoxP site 432-508 PolyA region554-1,357 Neo 1,358-1,944 PGK 1,948-1,981 LoxP site 1,997-2,339Intron 1 of EKLF gene 2,340-3,153 Exon 2 of EKLF gene 3,154-4,414Intron 2 of EKLF gene 4,415-4,946 Exon 3TaqMan Gene Expression Assay

RNA was prepared using TRIzol reagent (Invitrogen) and reversetranscribed using oligo-5 dT primer and SuperScript III ReverseTranscriptase (RT) (Invitrogen) according to standard procedures.Quantitative PCR (qPCR) using the validated TaqMan assays was carriedout on an Applied Biosystems 7500 Real-Time PCR System (AppliedBiosystems) instrument under default cycling conditions (50° C. for 2min, 95° C. for 10 min, 95° C. for 15 s, and 60° C. for 1 min for 40cycles). The relative EKLF (Mm04208330_g1 and Mm00516096_m1; AppliedBiosystems) expression levels were determined from a standard curve ofserial dilutions of the cDNA samples and then normalized to the β-actin(Actb:Mm00607939_s1; Applied Biosystems) or Gapdh (Mm999999151_g1;Applied Biosystems) expression levels.

Lifespan Measurement

Lifespan was measure using standard procedures. The life spans of theEKLF (K74R) knock-in mice were followed-up in specific-pathogen-free(SPF) animal facility.

Assay of Resistance to Tumorigenesis

To study the anti-carcinogenesis effect of EKLF (K74R) knock-in mice, alung colonization assay as described previously (Cha et al., 2003;Stackpole, 1981) was employed for the study. The murine metastaticmelanoma cells, B16-F10 (106 cells/0.2 mL), were injected intravenouslyinto the tail vein (i.v. injection) of EKLF (K74R) Kin mice and wildtype mice (3 mice per group), respectively, to examine the potentials oftumor formation from these cells and metastasis. B16F10 cells werechosen for test because they are derived from C57BL/6 mice andimmunologically compatible with the C57BL/6 mice (wild type and EKLF(K74R) knock-in mice). Two weeks later, the mice were killed byasphyxiation with CO2 and their lungs were removed for furtherexamination. Metastatic nodules on the surface of the lungs weremeasured by image analysis software (Image Inc.; Cha et al., 2003). Themeasurements of tumor number of each mouse were performed 14 days afterinjection.

Microarray Experiment

E14.5 mouse fetal livers or 3 months mouse bone marrow from WT and EklfK74R knockin mices were homogenized by repeated pipetting inphosphate-buffered saline (PBS) (10 mM phosphate, 0.15 M NaCl [pH 7.4]).Total RNAs were then isolated with Trizol reagent (Invitrogen) andsubjected to genome-scale gene expression profiling using the MouseGenome Array 430A 2.0 (Affymetrix, Inc.). Standard MAS5.0 method wasapplied to normalize the gene expression data. Gene expression valueswere log-transformed for later comparative analysis. Statisticalanalysis was carried out using R 3.0.2 language (R Development CoreTeam, 2013, www.R-project.org)

Quantitative PCR (qPCR) of EKLF Target Genes

The total RNAs were extracted by means of the commercial Trizol reagent(Invitrogen) and reverse-transcribed using SuperScriptIII according tothe manufacturer's protocol (Invitrogen). Mouse Cola1, Mpv171 and actinmRNA levels were determined by real-time PCR or semi-quantitative RT-PCRusing appropriate primers from Mission Biotech (Taiwian, ROC). The qPCRassays were performed using an Applied Biosystems 7500 Real-Time PCRSystem (Applied Biosystems, Foster City, Calif., USA) with the followingprofile: 1 cycle at 50° C. for 2 min, 1 cycle at 95° C. for 10 min, and35 cycles each at 95° C. for 15 s and 60° C. for 1 min. The thresholdcycle (Ct) was calculated by the instrument's software (7500 System SDSsoftware vers. 1.3.1). Actin served as an internal control, and therelative amount of Cola1 or Mpv171 mRNA was normalized to Actin. Dataare presented as histograms where each bar represents the mean±SEM ofdata derived from 3 times. semi-quantitative RT-PCR consisted ofpolymerase chain reactions (PCR) incubated at 94° C. for 5 min, followedby 22 cycles at 94° C. for 30s, 55° C. for 40 s, and 72° C. for 30 s(actin); 28 cycles at 94° C. for 30 s, 52° C. for 30 s, and 72° C. for27 s (Cola1) and 24 cycles at 94° C. for 30 s, 52° C. for 40 s, and 72°C. for 20 s (Mpv171), respectively. Data are presented as histogramswhere each bar represents the mean±SEM of data derived from 2 times.

Food/Water Intake Measurements

Spontaneous home cage activity was monitored using fully automatedcomputer vision analysis of continuous video recordings.

Metabolism Measurements

O2 consumption, CO2 production, food, and water intake were measuredusing the comprehensive lab animal monitoring system (CLAMS, Oxymax OpenCircuit Calorimeter, Columbus Instruments).

Insulin and Glucose Measurements

Blood samples were collected from mice. After spinning, the plasma wasused to quantify insulin and glucose by ELISA (Mediagnost, Germany)following the manufacturer recommendations. The plasma was also used toquantify glucose.

Grip Strength Test

The Grip Strength test was performed with the Muromachi, MK-380CM/Rapparatus. Experiments were recorded.

Rotarod Test

The rotarod test was performed with the Ugo Basile Rota-Rod 47600apparatus. For the testing sessions, the rotarod was acceleratedcontinuously from 2 to 80 revolutions per min.

Bone Imaging

Bone density was assessed using a Scanco Medical Micro-CT 40 instrumenton whole animals immediately after euthanasia.

Tumor Imaging

MicroPET images (MicroPET R4,) of mice were taken by scanning the miceat 0.5 h after administration of the mice with 100 Ci of 18F-FDG.

Example 1 Generation of EKLF K74R Mice

Transgenic mice carrying the EKLF K74R mutant allele were generatedaccording to procedures described in the “Materials and Methods”section. Schematic drawings of the target vector constructs forgenerating EKLF K74R mice are illustrated in FIG. 1A. Genomic DNA frommouse tails were analyzed by PCR and confirmed that both theheterologous and homozygous mice contained the EKLF K74R mutant allele(FIG. 1B). The EKLF K74R Knock-in mice bred normally and producedoffspring in the expected Mendelian ratios, indicating that thismodified EKLF gene functioned analogous to the wild type EKLF allele,and does not cause embryonic lethality. Quantitative mRNA analysis ofembryos indicated that EKLF K74R mice and wild-type littermatespossessed similar levels of total EKLF mRNA (FIG. 1D).

The EKLF protein is a transcription factor with promoter and repressoractivities. The transcriptome is changed by the K74R mutation. Asanalyzed by microarray hybridization, in either bone marrow or in E14.5fetal liver, at least 40 genes are down-regulated and up-regulated,respectively. As exemplified in FIG. 2, some of these expression changeshave been validated by PCR. The mRNA of Col1a1 was significantly reducedin the bone marrow of adult EKLF K74R knock-in mice compared towild-type type mice (FIG. 2A). The mRNA Mpv171 was significantly reducedin the E14.5 fetal liver of the EKLF K74R knock-in mice compared towild-type mice (FIG. 2B).

Example 2 EKLF K74R Mutation Leads to Enhanced Lifespan

The EKLF K74R transgenic mice had an extended lifespan compared towild-type littermates. Specifically, the median life span of the EKLFK74R mice (n=45) was 3 months longer, as compared with that of thewild-type mice (n=33) (FIG. 3A). Results of the lifespan study aresummarized in Table E2.

TABLE E2 Lifespan of EKLF K74R Mice Extended Median and Maximum Lifespanof EKLF K74R Genotype Maxi- Oldest Youngest (males) Mean mum Minimum 10%10% n K74R 32.2 ± 4.0 40.4 25.4 38.7 ± 1.5 26.5 ± 1.2 45 WT 29.5 ± 2.433.9 24.1 32.9 ± 0.7 24.9 ± 0.7 33

As evident from Table 1, the maximum lifespan (mean lifespan of theoldest 10% within a cohort) of the EKLF K74R male mice increased by 6.5months compared to wild-type littermates. The maximum lifespan of EKLFK74R mice was about 40 months, which was longer than other longevitymice reported in the literature, e.g., CISD2 (Wu et al., Human MolecularGenetics (2012) 21, 3965-3968). Furthermore, 32 month-old EKLF K74R micehad less grey hairs compared with that of the 17 month-old wild-typemice (FIG. 3B). The EKLF K74R mice were found to be healthy and grewnormally, in addition to their long life span.

Dietary restriction or caloric restriction has been performed on avariety of species, including the yeast, fish, rodents and dogs, todecelerate the biological aging process, resulting in increased lifespanand health span. Direct change of the metabolism also been reported toextended lifespan. Preliminary data of small-scale phenotypic analysisof mice on the normal chow diet are shown in FIGS. 4 and 5. As seen, thepatterns of the body weight changes of both wild-type and EKLF K74R micebetween 3 months to 24 months of age were similar (FIG. 4B). Indeed,48-hour spontaneous food intake, either normalized to body weight orexpressed as an absolute value, was similar between wild-type and EKLFK74R mice, as was the water intake (FIGS. 4C and 4D).

Normal chow-fed mice did not show obvious alterations of metabolicphenotypes, such as the oxygen consumption (VO₂, FIG. 5A), carbondioxide production (VCO₂, FIG. 5B), heat production (FIG. 5C), andrespiratory exchange ratio (RER) (FIG. 5D). These data suggested similaruse of lipids and carbohydrates as the energetic fuel sources in EKLFK74R mice as the wild-type.

Since dietary restriction or caloric restriction is often associatedwith alterations in glucose tolerance, we measured the bloodconcentration of fasting glucose and fasting insulin, as well as theability to clear glucose from the circulation in normal chow-fed mice.As seen in FIG. 6, there was no significant difference in fastingglucose concentration (FIG. 6A), fasting insulin concentration (FIG. 6B)or glucose tolerance (FIG. 6C) between the EKLF K74R and wild-type mice.

Tests were performed to evaluate muscle strength and motor coordination.The 3-month old EKLF K74R mice exhibited similar grip strength as the3-month old wild-type mice, but a significant increase of grip strengthwas observed for the 24-month old EKLF K74R mice when compared towild-type mice of the same age (FIG. 7A). On the other hand, thelatencies to fall from rotarod were similar between EKLF K74R mice andwild-type mice of either 3-month or 12-month of age (FIG. 7B). Thelatency to fall from an accelerating rotarod was measured in threetrials per day.

An important component of aging is osteoporosis. As seen in FIG. 8, bothbone volume and trabecular number declined with age in wild-type mice,whereas the trabecular spacing increased (FIG. 8, left panels). On thecontrary, all these parameters of old EKLF K74R mice wereindistinguishable from the young EKLF K74R animals, indicating that EKLFK74R mice did not develop osteoporosis when aging (FIG. 8; rightpanels).

The phenotypes observed in EKLF K74R mice differ from previouslydescribed long-lived mouse models. Table E3 shows a phenotype comparisonof the EKLF K74R mice to other known longevity rodent models. Upwardarrows indicate increase, downward arrows indicate decrease, and equalsigns indicate no change, as compared to the wild-type mice. For thecolumn of “Aging”, the comparison is for the old wild-type mice relativeto the young wild-type mice. This table is modified from Table S7 ofHofmann, et al. (2015) Cell 160, 477-488.

TABLE E3 Phenotypes of Mouse Models of Longevity Insulin Signaling Auto-IGF1 mTOR phagy Gene Mito- EKLF Met- IGF1R Pappa Pten Myc Mtor S6K1Fat10 Sirt1 stability chondria Aging K74R CR formin +/− −/− Tg +/− tgRapamycin −/− −/− Tg Atg5 p53 Tg Cisd2 Tg Median ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑↑ ↓ ↑ lifespan Maximum ↓ ↑ ↑ ↑= = ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↓ ↑ lifespan BodyMass ↑ = ↓ ↑↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ = ↓ ↓ = Adiposity ↑ = ↓ = ↓ = = ↓ ↓ ↓ ↑Body Temp = ↓ ↑ = = = = ↑ = = Cholesterol ↑ = ↓ ↓ = ↓ ↓ ↑ ↓= Cancer ↑ ↓↓ ↓ = ↓ ↓ ↓ ↓ ↓ = ↓ = = ↑ Serum IGF-1 = ↓ ↑ = ↓ ↓ = = Fibrosis ↑ ↓ ↓ = =↓ DNA damage ↑ ↓ ↓ = = Endogenous ↑ ↓ ↓ = ↓ = = oxidative stressSusceptibility ↑ ↓ ↑ ↑↓ = to chemical stress Fertility ↓ = ↓ = ↓ = ↓ = =Motor ↓ ↑ ↑ ↑ ↑ ↑ ↑ = ↑ ↑ ↑ ↑ coordination Bone density ↓ ↑ ↑↓ ↑ ↓ = ↑ ↓Senescence ↑ ↓ = ↓ Apoptosis ↑ ↑ ↑ ↓ = = ↓ Mitochondrial = = = ↑ ↑= = ↑↑ number Inflammation ↓ ↓ ↓ ↑ Susceptibility ↑ ↓ ↑ ↑ ↓ ↑ to infection

Example 3 EKLF K74R Mutation Leads to Cancer Resistance

Phenotypic observations showed lower age-related cancer incidence ratesin the EKLF K74R mice than in wild-type littermates, as exemplified bythe Micro-PET imaging analysis (FIG. 9A) and examination of dissected24-month old mice (FIG. 9B).

Cancer cells were implanted in EKLF K74R mice and wild-type littermatesby intravenous injection. B16F10 melanoma cells (ATCC# CRL6475) werederived from the same (C57BL/6J) genetic background as the EKLF K74Rmice. An in vivo metastasis assay was performed by tail vein injection(i.v. injection) of B16F10 cells into the mice (FIG. 10). Lungs wereexamined 2 weeks after injection of the B16F10 cells. These dataindicate that the EKLF K74R mice have reduced incidence of canceroccurrence. A preliminary study showed a non-statistically significantsmall trend towards reduced tumor growth in Kin mice when the B16F10melanoma cells were injected into the mice subcutaneously.

Together, these data showed a lower cancer incidence rate in the EKLFK74R mice (FIG. 9), which correlated well with the data of the lungtumorassay (FIG. 10). These data are consistent with EKLF K74R reducingor inhibiting tumor occurrence and reducing or inhibiting the metastasisof the cancer cells.

The detailed description provided herein in connection with the appendeddrawings is intended as a description of the present examples and is notintended to represent the only forms in which the present invention maybe constructed or utilized. The description sets forth certain functionsof the example and the sequence of steps for constructing and operatingthe example. However, the same or equivalent functions and sequences maybe accomplished by different examples. The various embodiments describedherein can be combined to provide further embodiments. Aspects of theembodiments can be modified, if necessary, to employ concepts of thevarious patents, applications and publications described herein toprovide yet further embodiments.

These and other changes can be made to the embodiments in light of theabove-detailed description. In general, in the following claims, theterms used should not be construed to limit the claims to the specificembodiments disclosed in the specification and the claims, but should beconstrued to include all possible embodiments along with the full scopeof equivalents to which such claims are entitled. Accordingly, theclaims are not limited by the disclosure.

All of the U.S. patents, U.S. patent application publications, U.S.patent applications, foreign patents, foreign patent applications andnon-patent publications referred to in this specification and/or listedin the Application Data Sheet, are incorporated herein by reference, intheir entirety.

What is claimed is:
 1. A method of reducing graying of the hair, ormuscle weakness; or increasing motor coordination, muscle strength, bonevolume, or bone density of a subject comprising: administering to thesubject an effective amount of a modified Erythroid Kruppel-like factor(EKLF) polypeptide comprising an amino acid modification that confersreduced sumoylation in a wild-type EKLF polypeptide, wherein, the aminoacid modification is a substitution of lysine with arginine at the aminoacid position 54 (K54R) of the wild-type EKLF polypeptide of SEQ ID NO:3.
 2. The method of claim 1, wherein the modified EKLF polypeptide hasreduced translocation from the cytoplasm to the nucleus as compared tothe wild-type EKLF polypeptide.
 3. The method of claim 1, wherein themodified EKLF polypeptide of the wild-type mouse EKLF polypeptide of SEQID NO: 3 further comprises a modification at position 68.